Agilent 8566B Operating and Programming Manual

Download

HEWLETT PACKARD

OPERATING AND PROGRAMMING MANUAL

8566B

SPECTRUM ANALYZER

100 Hz - 2.5 GHz/2 - 22 GHz

SERIAL NUMBERS

This manual applies directly to Model 8566B RF Sections with serial numbers prefixed 2410A and Display Sections with serial numbers prefixed 2403A.

1212 VALLEY HOUSE DRIVE, ROHNERT PARK, CALIFORNIA.94928. U.S.A.

IF-

MANUAL PART NO. 08566-90040 Microfiche Part No.

08566-90044

Printed: March 1984

CERTIFICATION

Hewlett-Packard Company certifies that shipment

from

the factory. Hewlett-Packard further certifies that its calibration measurements are traceable to the United States National Bureau calibration facility, and to the calibration facilities

thb

product met its published specifications at the time

Standards, to the extent allowed by the Bureau’s

other International Standards Organization

members.

WARRANTY

This Hewlett-Packard instrument product is warranted against defects in material and workmanship for a period of one year from date of shipment. During the warranty period, Hewlett-Packard Company will, at its option, either repair or replace products which prove to be defective.

For warranty service or repair, this product must be returned to a service facility designated by HP Buyer shah prepay shipping charges to HP and HP shall pay shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to HP from another country.

HP warrants that its software and firmware designated by HP for use with an instrument will execute its programming instructions when properly

installed

on that instrument. HP does not warrant that

the operation of the instrument, or software, or firmware will be uninterrupted or error free.

LIMITATION OF WARRANTY

The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer, Buyer-supplied software or interfacing, unauthorized modification or misuse, operation outside of the environmental specifications for the product, or improper site preparation or maintenance.

NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HP SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

EXCL USI YE REMEDIES

THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES. HP SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY

ASSISTANCE

Product maintenance agreements and other customer assistance agreements are available for Hewlett-Packard products.

For any assistance, contact your nearest Hewlett-Packard Sales and Service Office. Addresses are

provided at the back

this manual.

Section I

Manual Operation

Chapter 1 -GETTING STARTED Chapter 2 - DATA Chapter 3 - FUNCTION Chapter 4 - CRT Chapter 5 - TRACE Chapter 6 - MARKER Chapter 7 Chapter 8 - COUPLED FUNCTION

Chapter 9 Chapter 10 - INSTRUMENT STATE Chapter 1 1 - SHIFT Chapter 12 - USER Chapter 13 - PLOTTER OUTPUT

SCALE SWEEP

DISPLAY

AND

AND TRIGGER

KEY

DEFINED

REFERENCE LINE

FUNCTIONS

KEYS

GENERAL INFORMATION

GENERAL DESCRIPTION

GENERAL INFORMATION

The HP 8566B is a high-performance spectrum analyzer which operates from 100 Hz to 2.5 GHz in the low frequency band and 2 - 22 frequency tuning and an internal micro-computer to automate controls and provide useful operating features.

GHz

in the preselected microwave band. It uses a synthesized LO to provide accurate

HP 8566B SPECTRUM ANALYZER

The HP 8566B consists of an 85662A Display Section and an 85660B RF Section. Connect the two sections

along with the inter-connection cables as shown in the illustration below.

Connect interconnection cables as shown:

Line Module

85662A

Display Section

85660B

RF Section

Line Module.

Interconnect Cable Interconnect Cable

(85662-60093)

(85662-60094)

HP-IB

Connector

REAR PANEL CONNECTIONS

Manual Operation 1

INITIAL POWER ON

CAUTION

GENERAL INFORMATION

Before connecting the line power cords, make sure the appropriate line voltage and

line fuse have been selected for both the RF and Display sections of the analyzer. For complete information on line voltage and fuse selection, refer to the HP 8566B Operator’s Handbook. For information on line power cords for a specific country, contact the nearest Hewlett-Packard office.

INITIAL POWER ON

After making the AC power line connections, the STANDBY lights of both the RF and Display section should be

on. As long as the instrument is operating (LINE ON) or in STANDBY, the accuracy specifications of the internal frequency standard will be met. After a cold start, such as on-receipt of instrument, the analyzer requires 24 hours to stabilize prior to meeting specified performance.

INSTR

LINE ON AND STANDBY

CHECK LED

Upon LINE ON, the instrument will perform an automatic internal instrument check. If one or both of the red instrument check lights (INST CHECK I and II) remain on after this brief check routine, refer to the chart below to localize the problem.

LED On

Calibration

Problem

Digital Storage failure in 85662A

Interface Failure

Controller

(A15)

Check bus interconnect cable (85662-60094) Check bus interconnect cable (85662-60094)

and check if Al2 board is connected tightly Check if Al5 is connected tightly in 85660B

and that contacts are clean.

Solution

In order to meet specified frequency and amplitude accuracy, the analyzer’s calibration must be checked periodically to ensure the highest performance.

2 Manual Operation

GENERAL INFORMATION

RF INPUT

FREQZERO

Connect cable from CAL OUTPUT signal to RF input to perform initial calibration.

CAUTION

RF INPUT

Excessive signal input power will damage the input attenuator and the input mixer. The spectrum analyzer total RF power must not exceed + 30 dBm (1 watt).

DC Precaution: The HP 8566B cannot accept DC voltages in 0 dB

dB or greater input attenuation, a maximum of

damage. A blocking capacitor is recommended at the input when DC is present with an RF signal.

Manual Calibration Procedure

After instrument has stabilized, press

Press

8; this recalls the following stored control settings from the analyzer’s internal memory: Center Frequency = 100 MHz Frequency Span = 2 MHz Reference Level = - 7 dBm Res BW = 1 MHz Scale = 1 dB/Div Marker = Normal

Adjust AMPTD CAL for a marker amplitude of - 10 dBm.

4. Press

[1Ic1LLl

9; this recalls the following: Center Frequency = 100 MHz Frequency Span = 0 Hz Reference Level = - 7 dBm Res BW = 30 Hz Scale = 1 dB/Div Sweep Time = 10 Sec.

ATTEN.

k7V

DC can be accepted without

With 10

If connection cable has significant loss, it must be accounted for separately.

Manual Operation 3

CRT DISPLAY

Maximize amplitude response with FREQ ZERO adjustment.

Error Correction Routine

A 30 second internal error correction routine minimizes uncertainties due to control changes in the analyzer. To start the routine, press

A “CORR’D” readout will appear on the left edge of the CRT upon completion of this routine. If the message “Adjust AMPTD CAL” appears in the display, repeat the manual calibration before running the error correction

routine again.

(,,,,,

(%?I.

GENERAL INFORMATION

CRT DISPLAY

The analyzer’s CRT display presents the signal response trace and all pertinent measurement data. The active

function area names the function under DATA control and shows the function values as they are changed. All the

information necessary to scale and reference the graticule is provided.

MARKER

Reference User display

level

annotation amplitude

frequency

Active

function

readout

Center Resolution

frequency

’

PF’:

BW 1

bandwidth

LHX

YBW

100

Video

bandwidth

bun

17.wa

ass

CIHX

,TRACE

/TRACE

Internally

’

generated

graticule

Sweep time

span

PLOTTER OUTPUT

The trace data, graticule, and annotation on the analyzer’s screen can be directly output via HP-IB to a Packard plotter (such as the HP front pane1 of the analyzer.

4 Manual Operation

7245A/B,

7240A, 7470A, or 9872C) by pressing the LOWER LEFT key on the

Hewlett-

GENERAL INFORMATION

FRONT PANEL OVERVIEW

FRONT PANEL

OVERVI

IEW

Control Groups

CRT DISPLAY:

TRACE: 3 REFERENCE LINE: 4 SCALE:

5 KEY FUNCTION:

6 SWEEP and TRIGGER: 7

RFINPUT:

DATA/FUNCTION: 9

CAL OUTPUT:

MARKER:

COUPLED FUNCTION:

INSTRUMENT STATE:

13 LINE ON &STANDBY: 14

REORDER/PLOTTER

FUNCTIONS:

Signal response and analyzer settings

Control of signal response display Measurement and display aids Selects logarithmic or linear amplitude scale Access to special functions Selects trace update trigger

100 Hz to 22 GHz ( + 30 dBm max. power) Fundamental analyzer control Calibration signal Movable bright dot markers for direct frequency and amplitude readout Maintenance of absolute amplitude and frequency calibration by automatically selecting certain analyzer control settings Local

(1~1)

select key, SAVE and RECALL keys and FULL SPAN keys

Powers instrument and performs instrument check Controls output to recorder or HP-IB controlled plotter

Manual Operation 5

REAR PANEL OUTPUTS

GENERAL INFORMATION

21.4 MHz IF Output

IF Input/Output

Video Input/Output

Recorder Outputs

External Trigger

Sweep and Tune Output

Frequency Reference

10 MHz Output

Display Outputs

HP-IB Connector

Display Outputs

Display outputs allow all the CRT information to be displayed on an auxiliary CRT display such as the HP 1310A Large Screen Display.

Display Outputs

<75

nsec rise times. 1V full deflection.

output

<30

nsec rise time. Intensity: - 1V blank, 0 to

intensity modulation.

BLANK

TTL level

>2.4V

for blanking. Compatible with

most oscilloscopes.

Recorder Outputs

The recorder outputs allow the x-y plot of trace data with x-y plotters using positive

penlift

input. The front panel keys enable outputs for the calibration of x-y plotter reference points:

6 Manual Operation

coils or TTL

penlift

GENERAL INFORMATION

REAR PANEL OUTPUTS

Recorder

outputs

SWEEP

VIDEO

PENLIFT

21.4 MHz IF Output

RECORDER

LOWER UPPER

LEFT

RIGHT

A voltage proportional to the horizontal sweep of the CRT trace that ranges from OV for the left edge and to +

1OV

for the right edge.

Detected video output (before A-D conversion) proportional to vertical deflection of the CRT

trace. Output increases 100 mV/div from 0 to

A blanking output,

15V

occurs during CRT retrace; otherwise output is low at OV (pen down).

RECORDER Outputs

when keys or HP-IB

commands are enabled

Lower

Left

OV left

lower

+ 15v

Upper

Right

1ov

right

upper

15v

Sweep Plus

Tune Output

Sweep Plus Tune Output

10 MHz Output

21.4 MHz IF

21.4 MHz

IF OUTPUT

SWEEP + TUNE

OUT

Output

output

5052,

21.4 MHz output related to the RF input

to the analyzer.

In log scales, the IF output is logarithmically related to the RF input signal; in linear, the output is linearly related. The output is nominally - 20 dBm for a signal at the reference level. The analyzer’s resolution bandwidth setting controls the bandwidth. The input attenuator and IF step gain positions control the amplitude.

Output

l.OV per GHz of tune frequency,

Accuracy:

- lV/GHz

+ 2% -t

110 kQ

10mV

load.

10 MHz Output

MHzOUT

> - 5 dBm.

output

50R

output impedance

Manual Operation 7

REAR PANEL OUTPUTS

Frequency Reference Input/Output

GENERAL INFORMATION

To lock the spectrum analyzer to an external frequency reference, set the FREQ REFERENCE switch to

EXT.

Analyzer performance will be degraded unless frequency reference phase noise and spurious signals are < - 140

dBc single sideband (1 Hz) referred to 10 MHz at a 100 Hz to 10

the spectrum analyzer internal frequency reference, set the FREQ REFERENCE switch to

Frequency Reference

Input/Output

kHz

offset. To lock another spectrum analyzer to

INT

Input/Output

External Frequency Reference Requirements:

Frequency: 5 MHz & 50 Hz

EXT INT

Power: 0 to 10 dBm

Input Impedance:

10 MHz ? 100 Hz

5Of2

nominal

Internal Frequency Reference Characteristics.

Frequency: 10 MHz

Power: 0 dBm

Output

impedance: 5OQ

HP-IB Input Output Connector

The Hewlett-Packard Interface Bus allows remote operation of the analyzer as well as input and output of measurement data. See Section II of this manual.

IF and Video Connectors

The IF and Video connectors allow the 85650A Quasi-Peak Adapter to be used with the analyzer for

EM1

measurements

NOTE

When the Quasi-Peak Adapter is disconnected from the analyzer, make sure the IF INP connector connects to the IF OUT connector with one short BNC cable, and VIDEO INP connector connects to the VIDEO OUT connector with the other short BNC cable. Failure to connect the BNC cables will result in a loss of signal.

8 Manual Operation

GENERAL INFORMATION

REAR PANEL OUTPUTS

IF and Video Connectors

Input

21.4 MHz input. Input is nominally - 11 dBm

IF and Video Connectors

IF INP

VIDEO INP

(with spectrum analyzer input attenuator set to 10

dB) .5OQ

0 -

input impedance.

139Q

input impedance.

21.4 MHz output. Output is nominally - 11

IF OUT

VIDEO OUT

dBm (with spectrum analyzer input .attenuator

set to 10 0 -

dB) .5OQ

output impedance.

2V Output impedance < 10

kQ.

External Sweep Trigger Input

The External Sweep Trigger input allows the analyzer’s internal sweep source to be triggered by an external voltage.

External Sweep Trigger

Input

EXT TRIGGER

Must be

>2.4V (1OV

impedance.

Input

max) . 1 kQ nominal input

Manual Operation

GETTING STARTED

FRONT PANEL CONCEPT

Chapter 1

GETTING STARTED

GENERAL DESCRIPTION

This chapter is intended to provide you with a quick overview of the use and capability of the HP 8566B Spectrum Analyzer. The chapters following provide the details on each aspect of operation.

FRONT PANEL CONCEPT

The basic controls on the HP 8566B front panel consist of FUNCTION keys and DATA control keys. Functions are activated by pressing the appropriate key; its value is then changed via the DATA control knob, step keys or numeric keyboard. The activated FUNCTION will appear on the CRT as well as its current value.

FUNCTION/DATA

Controls

ACTIVE FUNCTION

and DATA

VALUE

The front panel controls are grouped by function. The majority of measurements can be made with only the FUNCTION/DATA group illustrated. The major FUNCTION controls are CENTER FREQUENCY FREQUENCY SPAN (or START/STOP FREQ),

and REFERENCE LEVEL. The value of the activated FUNCTION can be changed continuously with the knob, incrementally with STEP KEYS or exactly with the numeric keyboard.

Knob

Step Keys

Numeric Keyboard

MAKING A MEASUREMENT

Two FULL SPAN keys allow you to select a wide

Manual Operation 1 1

MAKING A MEASUREMENT

0- 2.5 GHz or 2 -22 GHz’ frequency span. Both

keys preset all the analyzer functions to automatically maintain a calibrated display during the course of the measurement.

Example

Connect the CAL OUTPUT signal to RF INPUT

Press

l%J

This presets the analyzer to a full 0- 2.5 GHz span with 0 dBm Reference level and automatically couples

al1

secondary receiver functions.

e&c 0.0 d&n .Tllh

GE-l-l-ING

--_.

-.' t -- --' -.'

t--

STARTED

'--

---

and use the knob

or the numeric keyboard to t

quency

to 100 MHz. Note that the activated FUNCTION (CENTER FREQUENCY) appears on the CRT graticule field.

Press

(91

or numeric keyboard to reduce the frequency

to 100

and use the knob

kHz.

, step keys

‘The

I’;:]

key is also activated with LINE ON.

12 Manual Operation

FREQUENCY

GETTING STARTED

DIRECT FREQUENCY AND AMPLITUDE READOUT

and use the knob 0, step keys

or numeric keyboard to position the peak of the

signal on the top graticule line.

The frequency and amplitude of the signal are read out from the graticule border. All secondary analyzer functions (resolution bandwidth, video bandwidth, sweep time, and attenuation) were automatically adjusted to maintain a

fully calibrated display. The coupled functions can also be uncoupled to allow manual operation.

For instance, to manually control the resolution bandwidth, press (::‘1 and change bandwidth with any combina-

tion of DATA control. The above also applies to I’:“:“) , @ ,

.-. -.

LEVEL

lzxrEu a...e.. m*

[,,,.)

, or

Pf5

ml 1

[‘::::‘1

I1 I I I

.“I

wn 3 L”,

SW’

1..

5pbN

3ae

Il..=

DIRECT FREQUENCY AND AMPLITUDE READOUT

.“I

Markers can be used to quickly identify signal frequency and measure signal separation or amplitude differences.

Activate a marker 02 the display with NORMAL. Tune marker with 0 . tude of the signal are read out with the marker.

To measure the harmonic(s) of the signal, press A and tune the second marker to the signal’s harmonic. The frequency separation and amplitude difference are read out.

The frequency and ampli-

amplitudes

-delta

(A) markers are available to

SAVE/RECALL GETTING STARTED

SAVE/RECALL

The HP 8566B instrument control settings can be saved in an internal memory and later recalled to make a measurement.

SHIFT KEYS

In addition to the front panel functions listed on the keys, another set of functions can be assigned to the same keys by pressing the blue B key prior to activating a front panel key. These will be covered in more detail in Chapter

11.

[I(c1111 m

provide access to the six internal storage registers.

AUTOMATIC MEASUREMENTS

The HP 8566B is fully programmable via the Hewlett-Packard Interface Bus (HP-IB) -HP’s implementation of IEEE STD 488-1975. Internationally, HP-IB is in concert with the IEC main interface document.

A computing controller/calculator can be used with the HP 8566B to configure an automatic measurement system. Just as the analyzer’s front panel is keyed manually to control functions and change values, simple program codes are transmitted via the HP-IB with a controller to make measurements automatically These program codes are listed in the Remote Operation section of the instrument pull-cards.

Detailed information on remote operation is found in Section II of this manual.

14 Manual Operation

DATA

DATA CONTROLS

CHAPTER 2

DATA

GENERAL DESCRIPTION

DATA controls are used to change function values for functions such as center frequency, start frequency, resolu-

tion bandwidth, or marker position.

DATA CONTROLS

The DATA controls are clustered about the FUNCTION keys which “call up” or activate the most frequently used

spectrum analyzer control functions: center frequency, frequency span (or start/stop frequency), and reference

level. The other functions that accept DATA control are shown below:

FRONT PANEL FUNCTIONS USING DATA CONTROLS

To the left of the FUNCTION Keys are the Data knob 0 and the DATA STEP keys to make incremental changes to the activated function. To the right of the FUNCTION keys is the DATA number/

units keyboard which allows changes to an exact value.

@ @

, which are used

Manual Operation 15

DATA ENTRY READOUT

The DATA controls will change the activated function in a manner prescribed by that function. For example, center frequency can be changed continuously with the DATA knob 0 , with the DATA STEP keys @ a , width, which can be set only to discrete values, can still be changed with any of the DATA controls. The DATA knob 0 and DATA STEP keys 13

from the number/units keyboard which may not coincide with an allowable bandwidth will select the nearest bandwidth.

or set exactly with the DATA number/units keyboard. Resolution band-

increment the setting from one bandwidth to the next. An entry

or in steps proportional to the frequency span

DATA

DATA ENTRY READOUT

DATA entries are read from the CRT display as they are changed.

PREVENTING DATA ENTRY

A function can be deactivated by pressing m . The active function readout is blanked and the ENABLED light goes out, indicating no DATA entry can be made. Pressing a function key re-enables the DATA controls.

DATA KNOB

The DATA knob 0 11a ows the continuous change of center frequency, frequency span (or start/stop frequencies), reference level, marker positions, display line, and threshold. It can also change the function values which are only incremented.

Clockwise rotation of the DATA knob will increase the function value. For continuous changes, the knob’s sensitivity is determined by the measurement range and the speed at which the knob is turned. For example, when the center frequency is activated, one quarter turn.

increases the value of the center frequency one horizontal division of span per

DATA STEP KEYS

The DATA STEP keys allow rapid increase @ or decrease

dependent either upon the analyzer’s measurements range, on a preset amount, fixed values, the next value in a sequence. Examples: Activate center frequency and frequency value by an amount equal to one division of the frequency span (one tenth of the frequency span). If the center frequency step size m has amount. If frequency span were activated, sequence. Activate resolution bandwidth

single step,

16 Manual Operation

hen

10)

and [&

preset,

would change the span to the next lower value in predetermined

will select the next widest bandwidth.

--I

of the active function value. The step size is

or,

for those parameters with

will increase the center

will increase the center frequency by that preset

Each press results in a

DATA DATA NUMBER/UNITS KEYBOARD

DATA NUMBER/UNITS KEYBOARD

The DATA number/units keyboard (or DATA keyboard) allows exact value entries to center frequency, frequency span (or start/stop frequency), reference level, log scale, marker positions, display line, threshold, and the COUPLED FUNCTIONS.

An activated parameter is changed by entering the number (with the CRT display providing a readout) then selecting the appropriate units key. The value is not changed (entered) until the units key is pressed.

The number portion of the entry may include a decimal, number. Corrections to number entries are made with

Example: With center frequency activated,

(TJ-Jp-JJQ[Z][Z]~@

:::,:

If not, the decimal is understood at the end of the

which erases the last digit for each press.

will set the center frequency to 1.250

If the units key were pressed without a number entry, 1 is entered (except in zero frequency span).

Negative DATA Entry

Negative entries from the number units keyboard can be made for power and frequency but not time and voltage.

Negative power entries can be made using -Z . The “ - dBm” key will enter - dBm, - dBmV or - dBpV For example, in reference level, with the dBmV units, an entry of

Negative frequency entries can be made using

as a prefix to the frequency entry For example, to enter a negative start frequency, press

p-J(TJ(TJ@~

Not all functions will accept negative entries (the sign will be ignored).

This enters the frequency value as - 100 MHz.

GHz.

““I

will enter - 50 dBmV

m-m

z; (g-m

MULTIPLE DATA CHANGES

A function, once activated, may be changed as often as necessary without reactivating that function (see Chapter 3, FUNCTION). Any of the DATA controls can be used in any order. l

It is not always necessary to make a DATA entry. For example, start and stop frequency may be activated simply to allow readout of the left and right display reference frequencies as start/stop frequencies.

l Exceptions are the SHIFT KEY FUNCTIONS which use only DATA number/units keyboard. See Chapter 11.

Manual Operation 17

FUNCTION GENERAL DESCRIPTION

CHAPTER 3

FUNCTION

GENERAL DESCRIPTION

This chapter describes the use of the major function block- CENTER FREQUENCY FREQUENCY SPAN (or START/STOP FREQUENCY), and REFERENCE LEVEL.

NCTION -

A FUNCTION is enabled by pressing the desired FUNCTION key Once enabled, the function, along with its current data value, is displayed in the active graticule area of the CRT as well as outside the graticule border. To change the value of the active function, use either the DATA knob, step keys, numeric keyboard, or a combination of all three. The HOLD key above the DATA knob can be used to retain the present instrument state and prevent any inadvertent entry of DATA. HOLD clears the active function area of the CRT as well as de-activates any

function.

Active

Function

Frequency

Span

Manual Operation

CENTER FREQUENCY

FUNCTION

The center frequency can be tuned continuously from 0 to 22 Additional band overlap enables the center frequency to tune up to 24 GHz and below to - 1

The center frequency can be set with 1 Hz resolution. Readout resolution is 1% of the frequency span, hence the highest readout resolution is obtained with narrow frequency spans. Data entered, however, is always accurate to

1 Hz even though the center frequency readout may display less resolution.

During band crossings (from 0 - 2.5 or above 22 Appendix for detailed information.)

DATA Entry with CENTER FREQUENCY

[-iEz]

GHz),

(EC)

. . . .

the frequency span may change to enable the desired center frequency to be set. (See

GHz

low band to 2 - 22

Changes the center frequency by about one half the total frequency span each full turn.

Changes the center frequency by one tenth of the frequency span, i.e., by one division. COUPLED FUNCTION size.

Allows direct center frequency entry. The analyzer will accept a center frequency entry with 1 Hz resolution. Even though the readout may show a fewer number of digits (due to wide frequency span), as the span is narrowed the full entry will be read out. Abbreviated readouts are not rounded.

GHz

using any combination of DATA controls.

GHz.

GHz

microwave band) or at band edges (below 0 Hz

[‘::::‘I

can be used to change this step

Example

Once a signal response is placed at the center of the display, the frequency of the signal can be read out from CENTER FREQUENCY The input signal is a 9 GHz synthesized source.

Press

1’6::)

for a full span display.

20 Manual Operation

Tune signal to center of display with

. . .

b -

I. *

.-I.*

! ! ! ! ! 1

(-ZZ)~.

FUNCTION

Reducing the frequency span will increase the center

frequency readout resolution.

Press

then

[Fj

(x]

FREQUENCY SPAN

The frequency span changes the total display frequency range symmetrically about the center frequency. Note that the frequency span readout refers to the total display frequency range; to determine frequency span per division,

divide by 10.

As the frequency span is changed, resolution bandwidth and video bandwidth automatically change to provide a predetermined level of resolution and noise averaging, respectively. Sweep time also changes automatically to maintain a calibrated display.

The analyzer can be adjusted to span a maximum of 2.5 GHz in the low band and 22 GHz (2 to 24 the microwave band. A minimum span of 100 Hz is allowed in both bands as well as 0 Hz (zero span) which enables the analyzer to function as a fixed-tune receiver. In zero span, the analyzer can display modulation waveforms in the time domain.

DATA Entry with FREQUENCY SPAN

Changes the frequency span continuously.

GHz

range) in

Changes the frequency span to the next value in a 1,

2,5,

10 sequence.

Enters an exact value up to three digits, depending on span. Additional

digits will be deleted without rounding.

Manual Operation 21

FREQUENCY SPAN FUNCTION

Example

Use FREQUENCY SPAN to zoom in on signals.

Connect CAL OUTPUT This selects a convenient

2.5

GHz.

to RF INPUT press full span display from 0 to

Tune center frequency to 100 MHz with:

100 MHz.

[06::1

[?%%-I

Reduce span with:

[F]@@or~

The desired span can also be selected with the

numeric keyboard. Note that narrow frequency spans

provide increased center frequency resolution.

In the microwave band, pressing

enables a 20

22 Manual Operation

GHz

full span.

FUNCTION

FREQUENCY SPAN

Example

Operating the spectrum analyzer in zero span. The modulation waveform of an AM signal can be displayed in the time domain.

In the frequency domain, we can accurately determine the modulation frequency and level.

I I I I

I.1

I” I

To demodulate the AM, increase the resolution band-

width to include both sidebands with the IF passband.

L-E-@@

Position the signal at the reference level and select a linear voltage display

(G&ii)gFJ

SCALE.

Manual Operation

START/STOP FREQUENCY FUNCTION

I/h

iii

To select zero span, press Video trigger can be used to trigger on the waveform. The sweep time control can be adjusted to change the horizontal scale.

[F)

START/STOP FREQUENCY

Another way to adjust the frequency range is by using START/STOP FREQUENCY instead of CENTER FREQUENCY and FREQUENCY SPAN. Activating START FREQ or STOP FREQ causes both to read out in place of CENTER FREQUENCY and SPAN on the CRT START FREQ sets the left graticule frequency and STOP FREQ

sets the right graticule frequency; both are mutually exclusive with CENTER FREQUENCY and FREQUENCY SPAN.

The INSTRUMENT STATE keys, w and m , select a start/stop frequency from 0 to 2.5 GHz and 2 to 22

GHz,

respectively. Additional over-range allows start frequency setting of - 1

The maximum start/stop frequency span allowable is 22

(START FREQ = STOP FREQ) .

GHz;

the minimum span is 100 Hz and zero span

GHz

and stop frequency of 24

GHz.

Start/Stop frequency readout resolution is 1% of the span (span = stop frequency - start frequency). Both start or stop frequencies can be entered with 1 Hz resolution.

DATA Entry with START/STOP Frequency

Changes the start or stop frequency. The amount of change per turn is a

constant percentage of the frequency span.

Changes the frequency by one tenth of the total frequency span.

Exact start or stop frequencies can be entered. The number of digits read out

depends upon the frequency span.

24 Manual Operation

FUNCTION

Example

Set start/stop frequency to monitor FM broadcast band

REFERENCE LEVEL

Press (?iiEiJ

unchanged, although the START/STOP frequency readouts are replaced by center frequency and span

(108 - 88 = 20 MHz).

Note that horizontal scaling is

t i iii ii i i i

,fYT

. . . .

YI.

IF5 mu

Ia. *“a

I i i i t

vs*

L”.

mu=

I”.. WI,

- 2... “...

REFERENCE LEVEL

The REFERENCE LEVEL function changes the absolute amplitude level of the top graticule line. The vertical scale (amplitude units per division) is selected from the SCALE control group. To measure signal level, the peak of the signal’s response is positioned on the top graticule line and its amplitude is read out from REF LEVEL.

The reference level can be adjusted from - 89.9 dBm to + 30 dBm ( - 139.9 dBm to + 60 dBm with extended range) with 0.1 dB resolution. The input attenuator is automatically coupled with the reference level to prevent gain compression; signals which are above the gain compression point will be displayed above the reference level line. Different mixer input levels as well as amplitude units can be selected (see

(L*lrl

FUNCTIONS Chapter 11).

Manual Operation 25

REFERENCE LEVEL

DATA Entry with REFERENCE LEVEL

In logarithmic scale, the changes are in 0.1 dB steps: in linear scale, the changes are made to the least significant digit.

FUNCTION

pi?-)

pJ@

In logarithmic scale, changes the reference level in steps according to

division scale. In linear scale, changes the reference level in 1 dB steps.

Allows entry of exact reference levels. Digits entered beyond the displayed number of digits are deleted.

Example

Measure amplitude of calibration signal.

Press

(-E]

100 MHz

dB/

[ “%?)

To measure signal amplitude, press

and

position signal peak to top graticule line. Read amplitude from REF LEVEL.

26 Manual Operation

; ,

FUNCTION

FUNCTION/DATA SUMMARY

CENTER

FREQUENCY

KNOB

Change continuously with up to 1 Hz

reso-

lution in narrow

STEP KEYS

spans.

Change frequency in one division steps

(i.e., 10% of fre- 5, 10 sequence.

@I@

NUMERIC

KEYBOARD Enter exact fre-

: t:: 1:::

rDJUSTMENT

RANGE

quency span).

quency with up to 1 Hz resolution.

1.000000000

:03.999999950

GHz

GHz. a

FREQUENCY

SPAN

m _

1 to

2.5 GHz

2 to 24

GHz

START/STOP

FREQUENCY

Change continuously

with n x 2 Hz resolu-

tion

- Change span in ” 2’

Enter

quency with n x 2 Hz

exact

fre- level. Digits entered

resolution *

100 Hz to 22 GHz and zero span.

106::

100 Hz to 2.5 GHz and zero span.

REFERENCE

LEVEL

Continuous with 0.1

dB tuning resolution.

Incremental change

in accordance with

log scale. In linear, changes incrementally in 1 dB steps.

Enter exact reference

beyond last displayed digit are deleted.

139.9

dBm

+60dBm.

READOUT

tESOLUTlON span),

* where n = harmomc number

1% of SPAN (Up to 1 Hz in narrow

0.1 dB in log; 4

nificant digits in lin-

ear.

sig-

Manual Operation 27

CRT DISPLAY

CHAPTER 4

CRT DISPLAY

GENERAL DESCRIPTION

This chapter describes the CRT display adjustments, readouts, and graphics.

ADJUSTMENT OF THE DISPLAY

ADJUSTMENT OF THE

The adjustments for intensity, focus, and alignment simultaneously affect all the lines and characters on the display.

CRT Display and Adjustments

DISPLKY

lNTENSlTY

Controls intensity for all the CRT writing.

A screwdriver adjustment which focuses all the CRT writing. Focusing any one element on the CRT focuses all the writing.

FOCUS

nLlGN

A screwdriver adjustment which tilts all the displayed CRT information.

DISPLAY SECTION LINE POWER

STANDBY

The light indicates power condition of the Spectrum Analyzer Display section as dictated by the LINE power switch on the 85660B RF section.

CRT DISPLAY OVERVIEW

The cathode ray tube of the Spectrum Analyzer Display section displays:

active function name and value

0 0

graticule

traces of the signal response

values that calibrate the frequency, time, and amplitude axes

values for the spectrum analyzer receiver parameters -that is, COUPLED FUNCTIONS. operator originated labels and graphics

Manual Operation 29

CRT DISPLAY OVERVIEW

Active Function

The function which has been activated for DATA entry is read out in the graticule area shown.

OFF 8 0 d&l .TTEN 18 dtl

!O do,

CRT DISPLAY

START

*.a c+I*

PFCI

BY 3

*Hz

Activating a function immediately writes its name in the active function area along with its present value. The

following summarizes the names and readout formats for the front panel designated active functions after an

INSTRUMENT PRESET

Function

FuNcT’oNc)

(,,,::c’)

COUPLED FUNCTION

I::‘1

pg)

Examples of Active

Function Readout

SPAN

20 GHz START

GHz

STOP

22 GHz

REF LEVEL

dBm

RES BW

3 MHz

VIDEO BW

3 MHz

SWEEPTIME

500 msec

vB*

5TB Z2.B M,

5111’ 5RB “...<

Function

I--)

(,,,.

(,.J(I*I(1lM

REFERENCE LINE

(,.,,,

Examples of Active

Function Readout

MARKER

12.0 GHz

19.8 dBm

MARKER A

20.0 MHz

12.4 dB

MARKER ZOOM

12.0 GHz

32.8 dBm

MARKER

12.0 GHz

140.4 dBm (1 Hz)

DISPLAY LINE

45.0 dBm

THRESHOLD

90.0 dBm

eactivates the active function and

bk$!s the

30 Manual Operation

active readout.

RF ATTEN

CF STEP

100 MHz

SCALE

KEY FUNCTION

(See

[,,,I

KEY FUNCTIONS,

Chapter 11.)

LOG

dB/

CRT DISPLAY

CRT DISPLAY OVERVIEW

Gralicule

The display graticule is an internally generated 10 division by 10 division rectangle for referencing frequency, time, and amplitude measurements. Double markings at the left, right, and bottom designate the center axes.

The graticuleThe graticule aspect ratioaspect ratio

ylx

= 1:1.3

ylx

= 1:1.3

Center line

The graticule may be blanked from the display with KEY FUNCTION

-b

Center lineCenter line

[

[unl

m and restored with

For CRT photography, the graticule may be intensified independent of the annotation and trace by pressing the

following sequence:

For more intensity, repeat the last two number entries, 1163 Hz and 2115 Hz. I’;:1 returns the graticule.to normal.

Traces

Three separate traces, A, B, and C, can be written onto the display. Each trace consists of 1000 separate

straight-

line elements drawn between 1001 fixed points across the CRT X and Y axis coordinates designate the particular

points between which the elements are drawn. Terms used to describe trace composition are defined as follows:

Point

A “point” in the context of this manual is a fixed location on the CRT display. There are

1,001 points along the X (horizontal) axis of the CRT graticule, numbered from 0 on the far left

graticule line to 1000 on the far right graticule line. Similarly, there are 1,001 points along the Y

(vertical) axis of the CRT graticule, numbered from 0 on the bottom graticule line to 1000 on the top graticule line. An additional 22 points of overrange available above the top graticule line provide the Y axis with a total of 1,023 points.

Manual Operation

3 1

CRT DISPLAY OVERVIEW

CRT DISPLAY

Display Unit

One display unit is the distance between two points (see above) along an X or Y

axis. The distance along the X axis between the far left graticule line and the far right graticule line is

1000 display units. The Y axis length between the bottom graticule line and the top graticule line is also 1000 display units. Although the Y axis can be extended another 22 display units above the top graticule line, the extended area is not calibrated.

X, Y coordinates to a particular point on the display are given in display units relative to X, Y

coordinates

Element

0,O

at the junction of the far left and bottom graticule lines.

An element is a distinct portion of the trace drawn on the CRT It comprises a point and the visible straight line drawn to it from the preceding point. An element drawn parallel with a vertical or horizontal graticule line is one diplay unit long. An element drawn at an angle to the graticule lines is longer, its actual length depending on the angle.

Vector

A vector is identical with an

Point of x, y coordinates

Overrange = 22 point

element,

except that it can be either visible or blanked.

Point of

x, y coordinates

-cr

1000.1000

Manual Operation

Point of x, y coordinates

0.0

TRACE DISPLAY TERMS

Graticule center x, y coordinates 500,500

Point of x, y coordinates

1000,0

NOTE

When the analyzer is operated manually (i.e., with its front-panel controls), the display size remains constant and the above definitions are fully applicable. When it is operated remotely with a controller, however, three additional larger display sizes are available through the display-size programming commands. For these larger-than-normal display sizes the lower left reference coordinates and the upper right trace limit expand beyond the CRT’s outer graticule lines. For further information on remotely-controlled

(i.e., programmed) display sizes, refer to commands

Dl,

D2, and D3 under Program-

ming Commands in Section II of this manual.

CRT DISPLAY CRT DISPLAY OVERVIEW

Locations of Permanent Readouts

The vertical and horizontal graticule axes are scaled by these readouts:

(iF

-5.4

1s 4”

Vertical scale

Center frequency

(or

start freq.)

CeNrm 4aa.e -

no3 I

1,.

h”l

vml 30 LHX

I...

PQ 3e I)..=

Frequency span (or stop freq.)

beI*

The COUPLED FUNCTIONS that describe the swept receiver characteristics of the spectrum analyzer are:

ATTEN ,a

RF attenuation

I,,

RerolLtion

bandwidth

V&e0

bandwidth

To blank all the character readouts, press KEY FUNCTION

Full\scale

svnep

time

(

o. To restore, press m p.

Manual Operation 33

CRT DISPLAY OVERVIEW

TRACE IDENTIFICATION

CHAPTER 5

TRACE

GENERAL DESCRIPTION

This chapter describes the use of the TRACE functions for writing, storing, and manipulating trace data.

G--

‘P

TRACE Controls

TRACE

‘Trace

Trace A

Trace C

TRACE IDENTIFICATION

Traces are differentiated by intensity. Trace A is bright, trace B and trace C are dim. i and m allow positive identification.

Manual Operation 35

TRACE MODES TRACE

TRACE MODES

Four mutually exclusive functions or modes for trace A and trace B determine the manner in which the traces are displayed. Indicator lights by the keys show the current modes.

WRITE Modes (sweeping):

m m

Displays the input signal response in trace selected.

Displays and holds th

e maximum responses of the input signal in trace selected.

STORE Modes (not sweeping):

[.,,. [,,,.,

Stores the current trace and displays it on the CRT display. Stores the current trace and blanks it from the CRT display.

Trace Memory

An understanding of the TRACE modes requires a description of the trace memory and trace data transfer within the analyzer.

Display traces are not written onto the CRT directly from the spectrum analyzer’s IF section. Instead, the analog signal response is converted to digital information and stored in one trace memory which can then be transferred

the CRT display. The way in which the information is displayed depends upon the TRACE mode selected.

RF Input

Memories

Analyzer

Video

Response

RF/IF

Sections

Data Updated at

Analog

Digital

Sweeptime

Rate

TRACE MODES DETERMINE HOW DATA IS ENTERED INTO

AND DISPLAYED FROM TRACE MEMORIES

’

Data Displayed at

Refresh

Rate

I I

The analyzer’s response is transferred into the trace memory at the sweep rate of the analyzer; that is, its sweep time. The trace memory is written onto the CRT display at a refresh rate of about 50 Hz, rapid enough to prevent flickering of the trace on the CRT Trace intensities remain constant as analyzer sweep times are changed.

36 Manual Operation

TRACE

NOTE

TRACE MODES

It is important to understand the difference between sweep and refresh.

Sweep

refers to the spectrum analyzer sweeping from a start frequency to a stop frequency and storing measured amplitude data into a trace memory.

Refresh

refers to the transfer of display memory data to the CRT display.

WRITE Modes

For the write modes, the analyzer signal response is written into trace memory during the sweep and the memory contents are displayed on the CRT

A(B)

Sets all the values in the trace memory A(B) to zero when first activated (bottom line graticule) , then displays the signal response.

A(B)

Latest signal response is written into the trace A(B) memory only at the horizontal positions where the response is greater than the stored response. When both m A and m B modes are selected, the analyzer writes into (sweeps) A and B alternately.

STORE Modes

In the STORE modes, no updating of the trace memory is made. The current memory data is saved.

(,,,,

A(B)

(,,1.. A(B)

The trace A(B) data are displayed on the CRT (that is, the refresh is enabled).

The trace A(B) data are not displayed on the CRT (that is, the refresh is disabled).

Example

With TRACE modes, signals can be observed as the analyzer sweeps, can be stored for comparison, erased, or monitored for frequency drift.

Center and zoom in on a 20 MHz signal: Press

Since

(Eiq

[F-

[‘s::l

p-J (-i-J @

has set m A and

(,,,.,1

B, only A is

displayed.

Manual Operation

TRACE

This response can be stored: Press

(,,,.

TRACE MODES

Write the same signal with B and change its position relative to trace A: Press m B.

[iii%-> a

Blank trace A; Press @ A. This trace can be recalled with m A as long as

A or

[21

A is not used first.

II\

i i

j iii

IIIIiI

: \

: !

‘I-, i i

; /

NOTE

The l on the top right corner of the CRT indicates that the CRT readouts may not correspond to the trace(s). In this case, the readouts

apply only to TRACE B and not TRACE A.

38 Manual Operation

TRACE

TRACE EXCHANGE

To display the drift of a signal, press a

(Simulate frequency drift with

(ZEC)

0.1

1e .”

liF .e &

ATlD4 10 Y

PI L !

Trace B sweeping Trace A

TRACE EXCHANGE

exchanges trace A and B, changing their relative intensities and storage memory locations and enables A

and B

[,..

. For example, in the trace display above, the modes and display appear.

Trace

Clear Write

Trace A

Max Hold

Press

Manual Operation

TRACE C MODES

TRACE

TRACE C MODES

A third trace, C, can be used to store a signal response. Trace C is not swept from the analyzer IF section as are

traces A and B, but is input using a trace B into C function (B

Access to the trace C modes is through KEY FUNCTION @ The modes are:

C) or a B and C exchange function (B z C).

View C: Blank C:

B-C:

(,,., (,,,,,

Displays trace C.

Blanks trace C from CRT display.

Writes trace B into trace C. Trace A and B modes are not changed. If trace C is not displayed, it remains undisplayed.

B*C:

Exchanges traces B and C. If trace B is displayed before the exchange, trace C is now displayed. If trace B is not displayed before the exchange, trace C is not displayed.

TRACE ARITHMETIC

TRACE arithmetic allows one trace to be modified by another trace or a display line position. A-B

A-B

[

Example

Trace arithmetic with the display line can be used to correct for the frequency response characteristics (flatness) of a

measurement

swept

Trace B amplitude (measured in divisions from the bottom graticule) is subtracted from trace A and the result written into trace A from sweep to sweep. Trace B is placed or kept in a STORE mode. Turns

[.-,-,I

off. Subtracts the amplitude of the display line from trace B and writes the result into trace B. Trace B is placed or kept in B Details on display line are in Chapter 7, REFERENCE LINE.

system typified by this setup:

where the device under test is to be characterized for insertion loss over a specific frequency range.

The analyzer and source are set to the proper amplitude level and frequency span with the source output connected directly to the analyzer input.

m (,,.

sweep source then

B, B.

40 Manual Operation

i i i

TRACE

The display line is activated and set below the source/ analyzer response.

DL[tlgll a.

The difference between the display line (in display

units) and the source/analyzer response is stored in

trace B with I’;:’

TRACE ARITHMETIC

Negative values of the

[‘;:II

line are stored even

though not displayed.

Now the device under test is connected between source and analyzer and its response is corrected for source flatness uncertainty by using

BA@.

1”“““’

sr- ..Y -

rnmllwo

w-s-

7.Y n

- 2e.. -me.

Manual Operation 41

TRACE PRIORITY

TRACE

TRACE PRIORITY

Functions which act upon a trace always act upon the highest priority trace. Priority is defined by the trace modes as follows:

Highest priority

view C

[,,..,]A

Lowest priority

Marker functions, for example, use trace priority to decide which trace to mark. See Chapter 6.

[.,,.,)B

blank C

42 Manual Operation

MARKER

GENERAL DESCRIPTION

Chapter 6

MARKER

GENERAL DESCRIPTION

This chapter describes the use of the MARKER and DATA controls for making many measurements faster and with greater accuracy. Markers can be displayed only on TRACE A and TRACE B.

Two types of functions make up the MARKER group; MARKER MODES, which enable or disable markers and their related functions; and MARKER ENTRY functions, which allow the scaling of the display frequency and amplitude using marker information.

Markers are bright spots which lie directly on the display trace. The horizontal position of an activated marker is controlled by the DATA controls. The marker can be positioned at a specific frequency with the DATA number/ units keyboard.

Readout of marker amplitude and frequency appears in the upper right of the display outside the

graticule.

When

a MARKER MODE is active, its amplitude and frequency readout also appears in the active function area of the

MARKER CONTROLS

Manual Operation

MARKER OVERVIEW

MARKER

MARKER OVERVIEW

FUNCTION

l Direct readout of the amplitude and frequency of a point along the trace. l Direct readout of amplitude and frequency differences between points on the trace.

Expansion of a span about a specific frequency.

l Placing a single marker at the highest response.

Automatic peaking of preselector.

Direct noise level readout.

Analysis of stored traces.

l Amplitude and frequency display scaling.

MARKER with

EEI

ZOOM

E @

(,,,lM

ENTRY

[,,,.

I”c”l-1

p!&jm

MARKER ON BUT NOT ACTIVE

An activated marker mode can be deactivated by activating another function, such as display line, or by DATA

I*OLD)

. This does not erase the marker itself nor the upper right display readout.

DATA control and active function readout will continue from its last position.

If the marker mode is reactivated,

If a marker mode is deactivated by a function (other than MARKER ENTRY) where a value change of the new

function results in a

resealing

of the amplitude or frequency axes, the marker will not stay on the trace. Reactivating

the marker will start it at the display center.

MARKER OFF

[

disables any marker mode, and blanks the marker readout from the CRT display. DATA controls are

disabled if the marker was active.

MARKER IN VIEW

MARKER m and a may be used on traces A or B in the view mode. This allows detailed analysis of responses which are nonperiodic or unstable.

The markers will be placed on a viewed trace according to the priority defined in Chapter 5, TRACE PRIORITY

SINGLE MARKER - NORMAL

activates a single marker at the center of the display on the trace of highest priority. Trace priority is defined in

Chapter 5. The marker will not activate on the TRACE modes

[--I

B, view C or blank C.

Measurement and Readout Range

Marker frequency has one digit more resolution than center frequency, and marker amplitude has one digit more resolution than reference level.

44 Manual Operation

MARKER

DATA Entry

SINGLE MARKER-NORMAL

Moves the marker continuously along the trace at about 5 horizontal divisions each full turn. The marker moves in display unit increments.

Moves the marker along the trace one tenth of the total width per step. moves marker to the right.

Places the marker at the frequency entered. An out-of-range entry results in placement of the marker at a graticule edge.

Example

Reading frequencies and amplitudes of signals is greatly simplified using MARKER

For a given display, activate the single marker with

then tune the marker with 0 to position it at

the signal peak.

The frequency and amplitude is read out in two display areas.

(--I

To read the left-hand signal’s parameters, move the marker to the signal peak with 0 .

The signal’s amplitude and frequency is read out directly.

Manual Operation

DIFFERENTIAL MARKERS-A

MARKER

DIFFERENTIAL MARKERS -

activates a second marker at the position of a single marker already on the trace. (If no single marker has

been activated, m places two markers at the center of the display.) The first marker’s position is fixed. The second marker’s position is under DATA control.

The display readout shows the difference in frequency and amplitude.

y(R 309.32 wz

Example

‘f/J

10 d”

-10.0

-2o.*

Measuring the differences between two signals on the

same display.

First ss the marker on one of the signal peaks with

(-IIo.

Activate m , movAthe second marker to the other signal peak with 0 ,

and read their differences

directly.

Fractional Differences

When the reference level is calibrated in voltage, marker m amplitudes are given as a fraction, the voltage ratio of two levels.

With logarithmic amplitude scale and the reference level in voltage, the fraction is based on the equation:

dB ddlerence

20 )

fraction = 10

Since this equation yields the harmonic distortion due to a single harmonic, its distortion contribution can be read

directly from the display.

46 Manual Operation

MARKER

DIFFERENTIAL MARKERS-A

Example

Set up m on the peaks of a fundamental (left) and its harmonic (right).

With the display referenced and scaled as shown, the readout

content. Percent is calculated as 100 x

“.0100X”

designates the fractional harmonic

(.OlOO)

= 1 .O%.

With a linear amplitude scale and a reference level calibrated in voltage, the fractional amplitude readout

is the simple linear ratio of the two markers.

Example

To measure % AM modulation from a spectra1 display, calibrate the display with the reference level in voltage and the amplitude scale in voltage.

Place the single marker on the carrier peak,

, and the second marker on one of the side-

band peaks, m 0 The fractional amplitude readout gives one half the modulation index .283.

%AM =

100x2x

.28 = 56%.

[--J

L INSR

. ..-.--

Measurement and Readout Range

The m function formats the amplitude readout according to reference level units and scale.

Reference

Level Units Logarithmic

SCALE

Linear

dBm

dBmV

Amplitude in

Amplitude in dB

dBpV

Voltage

Amplitude ratio

dB d,lferencr

20 )

AMPLITUDE READOUT FORMAT FOR MARKER

Ratio of marker amplitudes

Manual Operation 47

DIFFERENTIAL MARKERS-A

MARKER

The frequency readout for all MARKER of span measured.

The amplitude readout in dB has a resolution of f

depends upon the LOG m value:

DATA Entry

The minimum incremental change for m frequency is 0.1% of the frequency span.

E--JO

conditions has up to 4 significant digits, depending upon the portion

.Ol

dB for linear scale. The resolution for logarithmic scale

LOG SCALE

dB PER DIV

One full turn moves the active marker about one tenth of the horizontal span.

RESOLUTION

EI@@

One step moves the marker one tenth of the horizontal span.

Positive entry places marker higher in frequency than the stationary marker, negative entry places marker lower in frequency. Larger entries than allowable will place the marker on the adjacent graticule border,

Negative frequencies can be entered using a i m prefix as the minus sign. For example, to set a m span of 10 MHz with the second marker positioned to the left of the first, press

MARKER ZOOM

activates a single marker on the trace of highest priority (see TRACE

Ilo0.J

, the DATA knob and STEP keys change the values of different functions.

Positions Marker

PRIORIn

Chapter 5).

48 Manual Operation

Changes FREQUENCY SPAN and sets CENTER FREQUENCY equal to MARKER frequency

MARKER

DIFFERENTIAL MARKERS-A

DATA Control Use for

[,,,.

The marker can be moved along the trace with the DATA knob 0 , about the marker with DATA step @ and @ .

Each step also sets center frequency equal to the marker

frequency.

and the frequency span can be changed

Measurement and Readout Range

The measurement and readout range for marker zoom is the same as marker

DATA Entry

Moves the marker continuously along the trace. Rate dependent on speed of rotation. The marker moves in display unit increments.

Changes the frequency span to the next value in the sequence and sets the

El @J(g)

center frequency equal to the marker frequency.

Places the marker at the frequency entered. An out-of-range entry places

the marker at a graticule border.

Example

(UL)

In wide frequency spans, it is often necessary to expand a portion of the frequency span about a specific signal in order to resolve modulation sidebands or track frequency drift.

Manual Operation 49

DIFFERENTIAL MARKERS-A

From a full span, select a signal using the marker with

Eli.

To center the marker and signal and expand the frequency span in one step, press

Expanding twice more with @ @ shows that the marker requires recentering on the signal.

50 Manual Operation

MARKER

AUTOMATIC ZOOM

Recenter

with

Continue using @ (and recentering the marker on the signal when necessary) until the desired resolution is achieved.

AUTOMATIC ZOOM

The analyzer can automatically zoom in on a signal specified by a marker. The desired frequency span is input from the DATA number/units keyboard.

To use the automatic zoom function:

entify the signal to be zoomed in on.

and enter the desired span with the DATA number/units keyboard.

When the units key is pressed, the zooming process will begin.

Example

A single carrier needs to be examined in a 200 function automatically maintains the signal on the center of the CRT you can zoom automatically from a very wide span to a narrow span to look close-in at the signal.

kHz

span to see the sidebands. Because the SIGNAL TRACK

Manual Operation 51

PEAK SEARCH

MARKER

Place a marker on the carrier with B

Press @FJ (,,:,,,I

Enter the span.

F’;;ls

m @ B , and auto zoom will be

-Aid

1 I 1 A 1 I I

200 kt-42

I I I

PEAK SEARCH

Peak Search

Peak search places a single marker at the highest trace position of the highest priority trace. The active function is not changed.

Example

Use PEAR SEARCH to position the marker at the peak of the signal response.

In a narrow span, the marker may be placed at the signal peak.

Press m .

52 Manual Operation

MARKER

MARKER ENTRY

Note that the marker seeks the maximum trace response, no matter what the cause of the response. A larger signal, or the local oscillator feedthrough, would have attracted the marker.

MARKER to Next Peak

The marker can also find the next highest peaks by successively pressing

[,.,,,I

Marker to Minimum

The minimum trace value can be located by pressing

[

MARKER ENTRY

, m and marker m into span. Immediately set the corresponding FUNCTION value equal to the

readout of the active marker or markers:

ENTRY

marker frequency into

marker m frequency into i marker amplitude into

( ~&%%I j

(-1

RESULT

(IIIou(Iclj

spa”

@/;@

immediately records the single or the differential marker frequency in COUPLED FUNCTION

with

[z)

DATA @

I”.‘::‘]

for use

Manual Operation 53

MARKER ENTRY

A marker entry can be made any time a marker is on the trace. ( @ “r;;? with only one marker displayed takes 0 Hz as the lower frequency.) The active function will not be changed.

Example

MARKER

One of the fastest, most convenient ways to bring a signal to the center of the display is by using

Activate a

nal:

Change the center frequency to the marker frequency.

l”c:-]

will also work if start/stop frequencies are read out.

(,,,I 0

single

marker and tune it to the desired

sis-

l”r:-)

Example

One way to tune to a particular portion of a spectrum

being displayed is to use the A + span function.

Activate the single marker and place it at either end of the desired frequency span with

54 Manual ODeration

I--] 0

i i i

MARKER

Activate the second marker and place it at the other end of the span with m

MARKER ENTRY

Set the start and stop frequencies right marker frequencies with B

squal

to the left and

Marker m is activated.

A + span will work the same with start/stop frequency readout. Note that the markers can be placed at either end of the span.

Example

Here is a technique for viewing a fundamental and its harmonics (or any evenly spaced portions of the spectrum) with high resolution.

Narrow the span about the fundamental as necessary with m , centering the carrier.

Set the center frequency step size with

Now enable center frequency. With each 0 ,

suc-

cessive harmonics will be displayed.

Manual Operation 55

SIGNAL TRACK -AUTOMATIC FREQUENCY CONTROL

MARKER

70 e.

SECOND

-am-..

HARMONIC

a?“-“.

THIRD HARMONIC

+a ” e

FOURTH HARMONIC

Similar stepping can be accomplished using marker a into step size for intermodulation products or other evenly spaced signals such as communication channels.

SIGNAL TRACK - AUTOMATIC FREQUENCY CONTROL

The analyzer is capable of automatically maintaining a drifting signal at the center of the display To operate SIGNAL TRACK:

Press

[--1

, and place the marker on the signal to be tracked with

Press B to initiate the tracking. The light above the key indicates tracking. (Press again to turn off

As the signal drifts, the center frequency will automatically change to bring the signal, and marker to the center of

the display.

MARKER m , any other MARKER mode or the instrument preset turns the tracking function off.

Al-lVdl@-

I I

I I I I I

The upper sideband of a transmitter is to be monitored

I. ad

. .

as the carrier frequency is tuned.

Locate the sideband with [--y)

56 Manual Operation

MARKER

PRESELECTOR PEAK

The upper carrier sideband is tracked with m then zoomed in with

[T]

Q m (%1.

As the carrier frequency is changed, the sideband response will tend to remain in the center of the display. The center frequency and marker frequency reads out the sideband’s frequency.

A combination of

(::GKw:l

and a allows the “real time” signal frequency drift to be read on the display.

PRESELECTOR PEAK

Preselector peak automatically adjusts the preselector tracking to peak the signal at the active marker. When the

marker is tuned to a signal and m is pressed, an internal routine searches for the peak response of the preselector and adjusts the tracking accordingly. Using preselector peak prior to measuring a signal yields the most accurate amplitude reading.

Preselector peak operates with the peak search routine and then peak the response at that marker. A “PEAKING!” message appears on the active graticule area to indicate operation of the peaking routine. PRESELECTOR PEAK only operates in the 2 - 22

GHz

preselected band.

Example

Peak the signal for accurate amplitude measurement.

Tune marker to signal of interest.

Press @ 0 .

I--]

(,,,.

, or m markers. If the marker is OFF pressing m will initiate a

Manual Operation

NOISE

LEVEL MEASUREMENT

Press m to peak preselector tracking. Measure amplitude by reading marker.

MARKER

The specific preselector correction factor applied in the example above is stored. A

[15::)

INSTRUMENT PRESET will not erase the correction factor; however, another PEAKING routine in the same band will store a new correction factor in that band.

The factory set preselector tracking can be recalled with by pressing

(,,, / (“:::1

(See Chapter 11.)

[,,,

= @ The preselector can be manually adjusted

How It Works

The internal preselector peaking routine automatically searches and sets the peak response of the YIG filter at the marker frequency. Each peaking operation only affects the frequency band in which the signal is located (four possible bands). A correction factor, representing the tracking offset, is stored in memory for that particular band each time the peaking routine is used. Correction factors (one per band) remain in memory unless a new peaking routine is initiated that may result in a different number. The last m correction factors are saved along with control settings in the internal storage registers upon execution of a

I-11

followed by a number from 1 to 6. Thus,

up to six correction factors could be saved for any of the frequency ranges listed in the chart below:

(

BAND 1 FREQUENCY RANGE

2.0 - 5.8

5.8 - 12.5

12.5 - 18.6

18.6 - 22

GHz

NOISE LEVEL MEASUREMENT

When noise level is activated and the marker is placed in the noise, the rms noise level is read out normalized to a

1 Hz noise power bandwidth.

58 Manual Operation

MARKER

NOISE LEVEL MEASUREMENT

Noise level enabled: @

Noise level disabled:

[,,,,, b

The noise level measurement readout is corrected for the analyzer’s log amplifier response, and the detector response. The value is also normalized to a 1 Hz bandwidth.

Measurement and Readout Range

Noise level measures noise accurately down to 10 dB above the spectrum analyzer’s noise level. The readout resolution is in steps of +- 0.1 dB.

DATA Entry

See MARKER @ ,

[8)

, and

Example

In a communication system, the baseband noise level as well as signal to noise ratio measurements are required.

Select a frequency in the baseband spectrum clear of signals with a single marker. Press

IUI] 0

NOISE LEVEL MEASUREMENT

MARKER

Read the noise at the marker by pressing

The noise at 64 MHz is - 134 dBm in a 1 Hz bandwidth. This corresponds to - 134 dBm + 36

98 dBm in 4

kHz

voice channel bandwidth.

OBrl) b

dB/4

kHz =

Signal to noise measurements require the measurement of the noise level, as the example above, and the measurement of the absolute signal level.

Measure the power level of the turn the noise level off, press

fxiFJm

adp

signal. To

and read the

power level.

The signal to noise ratio referenced to 4

kHz

bandwidth is - 32 dBm - ( - 98

dBm)

= 66 dB.

*Normalization to a desired bandwidth uses the equation 10 log,0

60 Manual Operation

desired BW

(

1Hz

)

SCALE AND REFERENCE LINE

SCALE

Chapter 7

SCALE AND

REFERENCE LINE

GENERAL DESCRIPTION

This chapter describes the use of SCALE and REFERENCE LINE control groups for setting the amplitude scale, and for making amplitude level measurements more conveniently.

REFERENCE LINE

DISPLAY LINE

THRESHOLD

SCALE

SCALE keys allow the scaling of the vertical graticule divisions in logarithmic or linear units without changing the

reference level value.

LOG.

(DATA entry) scales the amplitude to 1 dB, 2 dB, 5 dB, or 10 dB per division.

If m is pressed when the scale is linear, 10 dB per division will be automatically entered. The subsequent

(DATA), if any, will then replace the automatic 10 dB/div.

Press

Manual Operation 61

SCALE SCALE AND REFERENCE LINE

LIN

d’l

imme

late

y scales the amplitude proportional to input voltage. The top graticule remains the reference level, the bottom graticule becomes zero voltage. Reference level, and all other amplitudes, are read out in voltage. However, other units may be selected. See AMPLITUDE UNITS SELECTION, Chapter 11.

If m is pressed when the scale is linear, 10 dB per division will be automatically entered.

LIN

Press

(

In LINEAR, a specific voltage per division scale can be set by entering a voltage reference level value. For example, to set the scale to 3 mV/division, key in 30 mV reference level, (Voltage entries are rounded to the nearest 0.1

dB,

so the 30 mV entry becomes 30.16 mV which equals - 17.4 dBm.)

DATA Entry

m(-j

Changes scale in allowable increments (1, 2, 5, or 10 dB per division).

pq @

Enables direct scale selection of allowed values. Other entries are rounded to an adjacent value.

LIN

No DATA entry will be accepted with the linear SCALE selection key,

Example

It is convenient to observe AM sidebands in linear as well as logarithmic scales for analysis of both modulation percentages and distortion products.

6.2 Manual Operation

SCALE

AND

REFERENCE

LINE

Modulated AM signal displayed in the 10 dB/division scale shows the carrier, its sidebands, and distortion products.

Linear scaling enables the observation of the sidebands proportional to the carrier.

LIN

Press

(-J

SCALE

As in the MARKER m example, Chapter 6, a direct readout of the percent modulation can be

made.

The fractional readout is one -half the modulation index (only one sideband is measured).

%AM = 2(.25) x 100 = 50%.

Note that the carrier signal need not be placed at the reference level for an index ratio measurement.

LOG Change to a logarithmic scale with m and change the dB/division with @ @ .

The sidebands are 12 dB down from the carrier, verifying the earlier measurement results.

I III I

Manual Operation 63

REFERENCE LINE SCALE AND REFERENCE LINE

Harmonic distortion of the modulating signal can be

measured as in MARKER m , Chapter 6.

The modulation frequency is 18.8

kHz

and the distortion caused by the second harmonic is 2.4% (read out as .024X).

REFERENCE LINE

The reference line functions, DISPLAY LINE (DL) and THRESHOLD (TH), place horizontal reference lines on the display. Their levels are read out in absolute amplitude units.

DISPLAY LINE uses

measure signal levels with direct readout.

establish a standard for go/no-go test comparisons. eliminate or reduce amplitude errors due to system frequency response uncertainty

THRESHOLD provides:

a base line clipper whose level is read out.

a minimum threshold level that can be set.

DISPLAY LINE

DISPLAY LINE amplitude, in reference level units, is read out on the left-hand side of the CRT display.

64 Manual Operation

[1.1113

(DATA entry) places a horizontal reference line at any level on the graticule. The line’s

SCALE AND REFERENCE LINE

DISPLAY LINE

The DISPLAY LINE can be positioned anywhere within the graticule. When activated after LINE power ON or

, the display line is placed 4.5 divisions down from the reference level.

DISPLAY LINE display line is activated again before LINE power ON or

DISPLAY LINE position is always accessible for HP-IB and TRACE m ,

erases the line and readout from the CRT display but does not reset the last position. If the

[a;l:l

, it will return to its last position.

even if never activated. See Chapter 5,

TRACE ARITHMETIC.

The DISPLAY LINE readout has the same number of significant digits as reference level.

DATA Entry

(go

m @@

@iiJH

Moves the line about one division for each full turn. The line moves in display unit increments.

Moves the line one-tenth of the total amplitude scale per step.

Positions the line to the exact entry level. Entry may be in

dBmV,

or f

dB&

depending upon which units are selected.

mV, FV -I-

dBm,

Example

When the amplitude of a number of signals in the same span require a quick readout, the DISPLAY LINE can be used.

Activate the DISPLAY LINE with

With

, place the line through the peak of a signal

and read out its absolute amplitude level.

-94.9

d%“V

Moving the DISPLAY LINE to each signal reads out its amplitude.

Manual Operation 65

THRESHOLD

SCALE AND REFERENCE LINE

THRESHOLD writing CRT spectrum analyzers. The boundary’s absolute amplitude level, in reference level units, is read out on

The THRESHOLD can be positioned anywhere within the graticule. It operates on TRACE m ,

for TRACES A, B, and C simultaneously. When activated after LINE power ON or

(,.,,.

(DATA entry) moves a lower boundary to the trace, similar to a base line clipper on

1’6::]

, the THRESHOLD is

direct-

The THRESHOLD level does not influence the trace memory; that is, the threshold level is not a lower boundary for trace information stored and output from the trace memories through the HP-IB. TH [ removes the THRESHOLD boundary and readout from the CRT display but does not reset the position. If threshold is activated again before LINE power ON or I’d::] , it will resume at its last level.

The THRESHOLD readout has the same number of significant digits as reference level.

DATA Entry

Moves the THRESHOLD about one division per rotation. The line moves in

Moves the THRESHOLD one-tenth of the total amplitude scale per step.

Positions the THRESHOLD to the exact entry level. Entry may be in

dBm, f dBmY or +

dB&

depending upon units selected.

mV,

(,.,.io

(t*ll.l

l pJ

66 Manual Operation

SCALE AND REFERENCE LINE

Example

The THRESHOLD can be used as a go/no-go test limit.

A series of signals can be tested for a specific THRESHOLD level by placing the THRESHOLD at the test level.

THRESHOLD

Press THRESHOLD

(,.,,,I

55.2 dBm. Only those sig-

nals > - 55.2 dBm will be displayed.

Manual Operation 67

COUPLED FUNCTION

GENERAL DESCRIPTION

Chapter 8

COUPLED

FUNCTION

GENERAL DESCRIPTION

This chapter describes the COUPLED FUNCTION group and its use in various measurements. The COUPLED

FUNCTIONS control the receiver characteristics of the spectrum analyzer.

The values of the COUPLED FUNCTION are automatically selected by the analyzer to keep absolute amplitude and frequency calibration as frequency span and reference level are changed. * The functions are all coupled with LINE power ON, a m or I”;‘:) FULL SPAN key, or when their individual

couples

Function

[1u10)

is activated.

COUPLED FUNCTION

Ill

I L

RES

BW {

ulLo”ples

Function

j 1

Center Frequency

Step Size

RF Attenuation

OFF

MANUAL

Light

Sweeptime, full scale

Video Bandwidth

Resdution Bandwidth

For each COUPLED FUNCTION:

AUTO

MA UAL

-:&s

Sets the function to the preset value dictated by the analyzer’s current state. The function is coupled.

Function value will not change with instrument state. DATA entry changes value. The MANUAL light goes on and stays on until the function is placed in m once again.

In most cases, the

[-1

coupled functions will change values to maintain amplitude calibration when one or more of the others are manually set. If the amplitude or frequency becomes uncalibrated, the right-hand side of the graticule.

*Center frequency step size does not affect amplitude or frequency calibration.

“MEAS UNCAL”

Manual Operation 69

appears in

DATA ENTRY FOR COUPLED FUNCTIONS

COUPLED FUNCTION

Coupled

Function

i::‘1

(::::‘I

[,1,,1

I’::::‘]

3 dB resolution bandwidth (IF filter) which largely determines the ability of the analyzer to

resolve signals close together in frequency. 3 dB bandwidth of the post detection low pass filter that averages noise appearing on the

trace. The total time for the analyzer to sweep through the displayed frequency span or display a

detected signal in zero frequency span. The setting of the input RF attenuator which controls signal level at the input mixer. Selects center frequency change for each DATA @

Selects

when

I=]

is activated.

DATA ENTRY FOR COUPLED FUNCTIONS

and

(.,,,.

Discrete values are entered for selects these values sequentially from the current value. A DATA entry from the keyboard which is not exactly equal to an allowable value will select an adjacent value. For example, bandwidth, the next higher IF bandwidth.

[:;‘I

[‘:“;“J

[‘I:::‘1

. The DATA entry from DATA

[::‘1

QQ@

and @j

will select 30

;,&J

kHz

RESOLUTION BANDWIDTH

[:;‘I

(DATA entry) sets bandwidth selection to MANUAL and changes the analyzer’s IF bandwidth. The band-

widths that can be selected are

1 MHz, and 3 MHz.

Example

10 Hz,30Hz,

100 Hz,

Hz,1kHz, 3 kHz, 10 kHz,

300

kHz, 100

kHz,

300

kHz,

A measurement requiring manual resolution bandwidth selection is the zero span (time domain) observation of modulation waveforms. An example can be found in Chapter 3, ZERO FREQUENCY SPAN - FIXED TUNED RECEIVER OPERATION.

70 Manual Operation

COUPLED FUNCTION

Another use of manual resolution bandwidth is for better sensitivity over a given frequency span.

The low level intermodulation products of a signal needs to be measured. With the functions coupled, the analyzer noise may mask the distortion products.

Reduction of the noise level by 10 dB (increased sensitivity) is achieved by decreasing the bandwidth by a factor of 10.

VIDEO BANDWIDTH

(THRESHOLD has been activated to clarify the dis-

play.

4l.B

The sweep time automatically slows to maintain absolute amplitude calibration if m is coupled.

VIDEO BANDWIDTH

[.;“.“)

(DATA entry) sets the video bandwidth selection to manual and changes the analyzer’s post detection filter bandwidth. The bandwidths

kHz,

100

kHz,

that can be selected are 1

300

kHz,

1 MHz, and 3 MHz.

Hz,

Hz, 10 Hz,30Hz,

100 Hz,

300 Hz, 1

kHz,

Manual Operation

7 1

VIDEO BANDWIDTH

COUPLED FUNCTION

Example

Signal responses near the noise level of the analyzer will be visually masked by the noise. The video filter can be

narrowed to smooth this noise.

A low level signal at this center frequency can just be discerned from the noise.

Narrowing the video bandwidth clarifies the signal and allows its amplitude measurement.

Press m @I @I @l

The sweep time will increase to maintain amplitude calibration.

NOTE

The video bandwidth must be set wider or equal to the resolution bandwidth when measuring pulsed RF or impulse noise levels.

Video Averaging

Narrowing the video filter requires a slower sweep time to keep amplitude calibration, since the narrower filter must have sufficient time to respond to each signal response. Video averaging is an internal routine which

djgjtalfy

averages a number of sweeps, allowing a more instantaneous display of spectra1 changes due to center frequency,

frequency span, or reference level changes. See Chapter 11.

72 Manual Operation

COUPLED FUNCTION

SWEEP TIME

(DATA entry) sets the sweep time selection to manual and changes the rate at which the analyzer sweeps the

displayed frequency or time span.

SWEEP TIME

The sweep times that can be selected are:

FREQUENCY SPAN

(~100

ZERO FREQUENCY

SPAN (0 Hz)

Hz)

SWEEP TIME

20 msec to 1500

psec

to 10

msec

20 msec to 1500

set

SEQUENCE

continuously

1,2,5,

and 10

continuously

Example

To identify signals quickly in a very narrow frequency span (where the resolution bandwidth would be narrow), the sweep time can be temporarily reduced (e.g., speed up sweep rate).

A frequency span of 10

kHz

will have a selected reso- lution bandwidth of 100 Hz and a sweep time of 3 seconds.

INPUT ATTENUATION

To quickly see signals present in the span, press and 0 several times. When the sweep completes

its span, couple sweep time again with

I::::‘1

COUPLED FUNCTION

ATID I.

10 al

Note that the

MEAS

UNCAL message appears automatically as the faster sweep time causes some distortion of the spectral response.

CEmn-

R1 By

1 ml*

lee H,

ve* 3.e H*

51p

I”

I...

Wm.0

INPUT ATTENUATION

I11111]

(DATA entry) sets the attenuation function to MANUAL and changes the analyzer’s RF input attenuation.

The levels of attenuation that can be selected are 10 dB to 70 dB in 10 dB steps, or 0 dB under special conditions.

Generally, the reference level does not change with attenuator settings.

.“Z

aam .Y M.

¶=ud 2” .*,

When the RF input attenuator function is coupled (AUTO), the value selected assures that the level at the input mixer is less than - 10 dBm (the 1 dB compression point) for on-screen signals. For example, if the reference level is + 28 dBm, the input attenuator will be set to 40

dB:

+ 28 dBm - 40 dB = - 12 dBm at the mixer.

The input mixer level can be changed to assure maximum dynamic range. See EFFECTIVE MIXER LEVEL, Chapter 11.

CAUTION

Greater than + 30 dBm total input power will damage the input attenuator and the input mixer.

74 Manual Operation

COUPLED FUNCTION INPUT

Zero Attenuation

As a precaution to protect the spectrum analyzer’s input mixer, 0 dB RF attenuation can only be selected from the

number/units keyboard, press

Reference Levels I - 100 dBm and > + 30 dBm

Reference levels 5 - 100 dBm or between + 30 dBm and + 60 dBm can be called when the reference level extended range is activated. Low reference level limits depend upon resolution bandwidth and scale.

Press

m (,1,.1

to extend the reference level range.

(,,,.1

@(x-

Al7ENUATlON

See Chapter 3, FUNCTION

Determining Distortion Products

If the total power to the analyzer is overloading the input mixer, distortion products of the input signals can be displayed as real signals. The RF attenuator can be used to determine which signals, if any, are internally generated distortion products.

Example

The two main signals shown are producing intermod- ulation products because the analyzer’s input mixer is overloaded.

(F)

and Chapter 11,

(,.,,,

KEY FUNCTIONS.

To determine whether these intermod products are generated by the analyzer, first save the spectrum displayed in B with @I B B B.

t i

- ,lb..l. LWS

lis L 1 h”Z

i ii i

VI 100

“a

Manual Operation

i i 1

9*H 1” .)u

JIP 1... .

CENTER FREQUENCY STEP SIZE

Increase the RF attenuation by 10 (If the reference level changes, it will be necessary to

return it back to its original value.)

dB.

Press m

1. .”

COUPLED FUNCTION

e -I..8 h

cwa-rm 1m.114 Y(*

- I I LCIX

Since some of the signal responses decrease as the attenuation increases (by comparing the response in A with the stored trace in B) , distortion products are caused by an overloaded input mixer. The high level signals causing the overload conditions must be attenuated to eliminate this condition.

1 I

YI 1.. “1

WIN 1” LHI

op 2.. ..*

1 ]

CENTER FREQUENCY STEP SIZE

(DATA entr ) sets step size to MANUAL, changes and stores the step size entered into a register. While

and

is in MANUAL, functions can be used to enter step size value to the register. When a CF STEP SIZE is AUTO, the center frequency steps will be 10% of the frequency span, even though the CF STEP SIZE register contains another value.

step size

SPAN or LINE power ON

I”::::il

&E-]

[,,,,

, [ FULL

(DATA entry)

change center frequency by the step size value stored in the register. Several

Entry Value

100 MHz

DATA entry value

uncoupled (MANUAL)

State

coupled (AUTO)

[“::::‘)

MARKER

The step size can be varied from 0 Hz to greater than 20 GHz with 1 Hz resolution. It is displayed with the same resolution as center frequency.

76 Manual Operation

marker frequency readout

uncoupled (MANUAL)

COUPLED FUNCTION

CENTER FREQUENCY STEP SIZE

When the center frequency is activated with step size in MANUAL, the active function readout includes both the center frequency and the step size value.

-En

I.25

-^ -

L)(s

i i i i

.-..

.“_

WAN

- 19. ---_

i I

2.5.

DATA Entry

(TFJQ

fig lF5[@

Changes the step size in display unit increments.

Changes the step size in steps equal to one-tenth of the frequency span.

Selects a specific step size to a resolution equal to the current center frequency readout.

Example

Surveillance of a wide frequency span sometimes requires high resolution. One fast way to achieve this is to take the span in sequential pieces using a tailored center frequency step. This example looks from 0 Hz to 2.5

GHz

50 MHz spans.

First set the span and center frequency: For a span of

50 MHz, press

center frequency to 25 MHz with

(5)

m @

Set the

[z)

Q(ul.

t i 1 i1 I I

m 25..

-IlLHI

ml=

I I

vml 3ee

I 1

I I

LIHZ

Manual Operation 77

¶w 2e

I I

WAN

se.. ma=

I)...

CENTER FREQUENCY STEP SIZE

COUPLED FUNCTION

Set the step size to 50 MHz, reactivate center frequency with

(‘::::‘I

[Zg)

and step to

225 MHz.

cwnw

f---3

Now each u sets the center frequency to the next 50 MHz span for a span by span surveillance of the spectrum. (Center frequency = 25 MHz, 75 MHz, 125 MHz, etc.) Center frequency step size can also be defined

by the marker. See the MARKER ENTRY portion of Chapter 6.

78 Manual Operation

SWEEP AND TRIGGER

Chapter 9

SWEEP AND TRIGGER

This chapter describes the use of SWEEP and TRIGGER control functions.

SWEEP controls enable:

continuous, or repetitive sweeping (sweep time L 20 msec) .

a single sweep which will repeat only on demand (sweep time I 20 msec) .

TRIGGER controls select the function which will begin a sweep:

as soon as possible,

[.,,

line voltage passes through zero on a positive swing,

an external signal voltage passes through - 1.5V on a positive swing.

[,,,I

the level of a detected RF envelope reaches up to the level on the CRT display determined by the

LEVEL knob.

SWEEP

TRIGGER

SWEEP AND TRIGGER CONTROLS

SWEEP

The spectrum analyzer frequency sweep (sweep times from the start frequency to the stop frequency unless new data entries are made to the analyzer from the front panel or the HP-IB. With faster sweeps, changes to center frequency, for example, appear continuous. With long sweep times, a change in center frequency noticeably suspends the sweep while the analyzer updates its state and readout, then the sweep continues from where it was, tracing out the new spectrum.

220

msec), once triggered, continues at a uniform rate

Manual Operation 79

TRIGGER

SWEEP

AND

TRIGGER

The SWEEP light indicates that a sweep is in progress. The light is out between sweeps and during data entry. (The

light is out for sweep times

110

msec.)

After a sweep, the next sweep will be initiated only if:

continuous sweep mode is selected or a single sweep demand is made,

the trigger conditions are met,

l data is not entered continuously from the front panel DATA controls or the HP-IB.

Continuous Sweep

[-1

enables the continuous sweep mode. Provided the trigger and data entry conditions are met, one sweep will

follow another as soon as triggered. Pressing m initiates a new sweep.

Single Sweep

enables the single sweep mode. Each time

[,,,,,,I

is pressed, including when the SWEEP mode is changed

from continuous, one sweep is initiated provided that the trigger and data entry conditions are met. A sweep in

progress will be terminated and restarted upon (,,.,,, .

Zero Frequency Span Sweep

In zero frequency span, sweep times from 1 psec to 10 msec are also available. In these sweep times, the SWEEP

[,,,)

, @ are disabled. The video signal response is not digitally stored (trace modes also disabled), but multiplexed directly onto the display along with the graticule and readouts. The graticule and readouts are refreshed following each fast sweep.

To avoid flicker of the display when external or video triggers are less frequent than 25 msec, the analyzer will

trigger internally. If triggers dependent only on external or video trigger are required, press

[,nl) ‘(d’

11.111) ‘[,,,,

isa

es “auto” external trigger feature

disables “auto” video trigger feature

For zero frequency span sweep times

NOTE

110

msec and

11*111)

x or @ y, the CRT display graticule and readout depend upon triggering. If no trigger is present, the CRT display will be blank.

TRIGGER

The analyzer sweep is triggered by one of four modes selected.

(:2:.,

allows the next sweep to start as soon as possible after the last sweep.

allows the next sweep to start when the line voltage passes through zero, going positive.

[

allows the next sweep to start when an external voltage level passes through =

The external trigger signal level must be between OV and +

80 Manual Operation

1.5V,

going positive.

SWEEP AND TRIGGER

allows the next sweep to start if the detected RF envelope voltage rises to a level set by the LEVEL

EXTERNAL TRIGGER INPUT

TRIGGER

knob. The LEVEL corresponds to detected levels displayed on the CRT between the bottom graticule (full CCW) and the top graticule (full CW).

An RF envelope will trigger the sweep only if it is capable of being traced on the CRT display-that is, the resolution bandwidth and video bandwidth are wide enough to pass the modulation waveform of an input signal.

Example

A zero span display of this video waveform will trigger for all LEVEL knob settings.

If the video signal lowers on the display, the LEVEL must be set towards the minus side.

If the level does not cause a trigger within 25 msec, the sweep will be triggered anyway to ensure a display. Note that this is true only for sweep times

~10

msec.

Manual Operation 81

INSTRUMENT STATE

FULL SPAN INSTRUMENT PRESET (2 - 22

GHz)

Chaper 10

INSTRUMENTSTATE

GENERAL DESCRIPTION

This chapter describes the INSTRUMENT STATE keys. Each key allows access to or activation of a specific set of

functions and their values. Some of the sets are built into the

analyzerand

some are user defined.

INSTRUMENT STATE

Instrument states that can be selected:

FULL SPAN

m(TJ

@(TJ

FULL SPAN INSTRUMENT PRESET (2

provides a convenient starting point for making most measurements. That is, it calls for a full 2 - 22 GHz span, coupled functions, and a 0 dBm reference level, to name a few. LINE power ON automatically calls for an instrument preset.

A full 2-22 GHz span with coupled operation and all the functions set to known states and values.

A full 0 Hz to 2.5 GHz span with coupled operation and all the functions set to known states and values. Saves the complete set of current front panel function states and values for later recall. Registers 1

through 6 are available for storage.

Recalls the complete instrument state saved in the register called. Calls for front panel control after the analyzer has been placed in a remote state by an HP-IB controller.

22 GHz)

The states that are set include all the functions and values of

l front panel functions, and

[,.,,11

KEY FUNCTIONS, and

l functions accessible only by the HP-IB.

Manual Operation 83

FULL SPAN INSTRUMENT PRESET (2 - 22

GHz)

INSTRUMENT STATE

Front Panel Preset

enables all the front panel functions designated by keys with white lettering. It will save a trace response in

TRACE B, but not A or C.

To be precise:

FUNCTION:

DATA: COUPLED FUNCTION:

TRACE:

,m,

FUNCTIONS ACTIVATED WITH FULL SPAN KEY

Start Frequency Stop Frequency Reference Level

2 GHz 22

GHz

0 dBm

Hold All set to a which corresponds to the following values:

Resolution Bandwidth Video Bandwidth Sweep Time Attenuator

3 MHz

1MHz

500

msec

dB,

full scale

coupled to maintain < - 10 dBm

at input mixer

Center Frequency Step Size A

100 MHz entered in register

Clear-Write Blanked, but information in memory saved

A-B

off

MARKER: INSTRUMENT STATE

I,.,and@:

SCALE: REFERENCE LINE:

84 Manual Operation

off

States are saved including the current state. See @ a below.

Logarithmic, 10 dB/division Display line off

Threshold off

5.5 divisions up 1 .O divisions up

INSTRUMENT STATE

FULL SPAN 0

2.5

GHz

SWEEP: TRIGGER:

INSTR CHECK:

KEY FUNCTION:

[auto] FUNCTIONS:

HP-IB FUNCTIONS:

Continuous Free run An internal instrument check is made. If the check is false, lights will stay on. Normal

Chapter 11, instrument preset during

KEY FUNCTIONS, discusses the implications of activating

[,.,,

FUNCTION use.

If the key is activated (shift light on), m unshifts the key. This is equivalent to

pressing

“Dl”

“EM”

“03”

“PD”

“DA’

Graphic information or control language written into the analyzer memory by

[--I

Display size-normal

Erase trace C memory Output format ASCII absolute Pen down Display address set to 3072

HP-

IB functions such as graph (GR) , plot (PA), label (LB), or display write (DW) will be erased unless stored in trace memory B. Instrument preset also rewrites all the display graticule and character readouts into the appropriate section of the display memory.

FULL SPAN 0 - 2.5

The 0 - 2.5

GHz

FULL SPAN key selects a start/stop frequency of 0 Hz and 2.5 GHz respectively, a reference

GHz

level of 0 dBm, and sets all the COUPLED FUNCTIONS to AUTO. Basically, B is the equivalent of an instrument preset in the low band. It presets everything that m does except that m will not execute the instrument check sequence.

SAVING AND RECALLING INSTRUMENT STATES

[

(DATA keyboard entry) and @ (DATA keyboard entry) save and recall complete sets of user-defined

front panel function v lues. The DATA entry from the keyboard names the register which stores the instrument

state. Six registers, The registers contain their last states even with a loss of line power (power failure). The registers are maintained with an internal battery supply for about a 30-day period after line power failure.

@gr;7

is a special recall function which recalls the instrument state prior to the last instrument preset or single

function value change, whichever has most recently occurred. It aids in recovering from inadvertent entries.

Registers 8 and 9 contain preset control settings that are used for calibration purposes. (See Calibration procedure

under GENERAL INFORMATION at the beginning of this section.) Register 0 restores the current state of the

analyzer, which is useful for servicing.

through @ ,can be saved and recalled. Only another [ will erase a saved register.

The current instrument state, if the POWER switch is turned to STANDBY can be recovered at POWER ON if

is activated previous to a power loss.

or a short-term loss of ac line power),

(

Manual Operation 85

SAVING AND RECALLING INSTRUMENT STATES

Some

[,..,

KEY FUNCTION values or states cannot be saved. Neither can information in the display memories,

INSTRUMENT STATE

such as a title or trace.

Example

When a test sequence is used over and over, the instrument states can be set up in the registers prior to testing for recall during the procedure.

Keying in a specific state:

(ZE--@p-J@ [~](gYi-J~~

[y)@

LIN ( SCALE Then save with

Press

[,., Q

(06::)

And recall the last state with

(llellll

[1]

Once the state has been recalled, any function can be used for more detailed measurements.

Note that in this case, the state could also have been recalled by

(.,,.rrl

[1] .

Registers 1 - 6 can also be locked to prevent any loss or change in the contents of the storage registers.

[,.lrl

I-11

locks the registers and

(,.,,, (..cLLL

unlocks the

registers.

86 Manual Operation

INSTRUMENT STATE

LOCAL OPERATION

enables front panel control after an HP-IB remote LISTEN or TALK command has been executed. An HP-IB local lockout will disable

STANDBY

then ON again.

until an HP-IB return to local command is executed or the LINE power is turned to

Indicates instrument has been addressed through

HP-

IB.

Indicates instrument is in remote operation.

The addressed light remains on until an HP-IB device clear command or any unlisten command is executed.

Manual Operation 87

(,,,rr

KEY FUNCTIONS

GENERAL DESCRIPTION

Chapter 11

KEY

FUNCTIONS

GENERAL DESCRIPTION

This chapter describes access and use of the B KEY FUNCTION.

Shift functions supplement a front panel function or provide unique measurement capabilities. The @ functions are not named on the front panel but are coded by the blue characters beside the keys.

frequency offset function is designated by the code V On the front panel the code V is found in the FUNCTION

section :

For-

example, the

The shift functions are activated by pressing complete summary of shift FUNCTIONS is in this chapter under FUNCTION SUMMARY There is an index to all shift functions at the end of this chapter.

Example

Activate the shift function V (frequency offset) with

press

The shift light can always be turned off with

DATA Entry

An active shift function value is read out and identified in the active function area of the display the same as any other function using DATA entry Once the data has been entered, any other function can be activated. The shift function will retain its last value until the a key is pressed, or the LINE switch is switched to STANDBY

[

does not disable the selected shift function (except for title).

shift light on

shift light off and offset function activated

(WTII

and then the front panel key with the appropriate blue code. A

I--u]

which returns the front panel keys to their designated function.

Manual Operation 89

FUNCTION SUMMARY

KEY FUNCTIONS

General

r HP-IB Service request

P Enter HP-IB address

Power on in last state

Display Address

Display Write

Amplitude

Z Amplitude offset

A Units: dBm

B C

dBmV dB@

D voltage

I Extended reference level

range

Negative entry

, Mixer level

Marker

Marker to next peak N Marker to minimum 0 Enter A+ span M Noise level on

L Noise level off u

Stop single sweep at marker = Factory preselector setting

Manual preselector setting

Display

o Annotation blanked p Annotation on

w Display correction data

g CRT beam off h CRT beam on

m Graticule blanked

n Graticule on

Title

Trace

A+B-+A

Detection:

normal

positive peak

d negative peak

sampling

Trace C:

blank trace C

B?t,C

B-C view trace C

G Video averaging on H Video averaging off

Trigger-Zero Span

without 25 msec triggering

Instrument State

( Save registers locked

) Save registers unlocked

Fast preset 2 - 22

Fast preset external mixer

GHz

S Fast HP-IB operation

t Band lock

Q Band unlock

Error Correction

W Execute routine

X Use correction data Y

Do not use correction data

w Display correction data

Diagnostics

w Display correction data

q Disable step gain R Frequency diagnostic on F YTO pretest mode

J Manual DACS control

Turns off YTX self-heating

correction

Frequency

V Frequency offset

Negative entry

Signal identifier ext. mixer

ALPHABETICAL KEY CODE SUMMARY

*A Amplitude in dBm

B Amplitude in dBmV C Amplitude in dBpV D Amplitude in voltage

Title

F Removes IF Offset for YTO

preset

G Video averaging on

Video averaging off

I Extended reference level

range

J Manual DACS control

Marker to next peak

Noise level off M Noise level on N Marker to minimum 0 Enter A + span

P Set HP-IB address

Q Band unlock

R Frequency diagnostic on S Fast HP-IB operation

Fast preset 2 - 22 GHz

Fast preset external mixer

V Frequency offset

W Execute error correction

routine

X Use correction data

Do not use correction data

Z Amplitude offset

*a Normal detection

b Positive peak detection c

A+B-‘A

d Negative peak detection e Sample detection

Power on in last state g CRT beam off

CRT beam on

BsC

j View trace C

Blank trace C

B-C

m Graticule blanked

‘These functions selected with [‘a.‘:l INSTRUMENT PRESET

Graticule on

o Annotation blanked

Annotation on

q Disable step gain

r HP-IB service request

t Band lock

Stop single sweep at marker

Signal identifier ext. mixer

w Display correction data

111

without 25 msec triggering

ll=o

without 25 msec triggering

Display address

Negative entry

= Factory preselector setting

Manual preselector setting

( Save registers locked

) Save registers, unlocked

I Display write

Mixer level

Turns off YTX self-heating

correction

90 Manual Operation

151111

KEY FUNCTIONS

DATA entries to shift functions are made only from the number/units keyboard. The ENABLED light remains off even though data may be entered.

Data is entered (that is, changes the instrument state) only when a units key is pressed. If the entry has no units (an address, for example), use the0p!!.

key as the terminator.

(,.,,, -,v,z

NEGATIVE DATA KEYBOARD ENTRY

Entering negative data from the DATA keyboard requires the use of a negative symbol prefix on the number entry.

Negative entry:

For example, to enter a negative 100 MHz offset frequency:

Press &

Press (,..I] (-I

Not all values can be entered with a negative prefix. For example, a negative entry to a voltage reference level will

result in entering the positive value.

Negative entries in dB can be made with the - dBm units key or the negative prefix with the + dBm units key. If both negative prefix and

[,.,,, (

[z)

to activate frequency offset.

-7;:

m @

are used, the value will be entered as positive.

to enter a negative frequency.

FREQUENCY AND AMPLITUDE OFFSET

The CRT display amplitude and frequency readout can be offset. Entering an offset does not affect the trace.

Frequency offset:

Amplitude offset:

Offset entries are added to all the frequency or amplitude readouts on the CRT display, including marker, display line, threshold, start frequency, and stop frequency.

FUNCTION

To eliminate an offset, activate the offset and enter zero. A FULL SPAN key also sets the offsets to zero.

Offsets are stored with the

(,,,,I [=I

[,,,

functions for recall with

(DATA keyboard entry)

(DATA keyboard entry

Manual Operation 91

When an offset is entered, its value is displayed on the CRT

iji

i”“;?

KEY FUNCTIONS

i i

DATA entry from the keyboard can be in Hz, amplitude. The amplitude offset readout is always in dB. An entry in voltage can be made and will be converted to

offset.

The offset range for frequency is - 99.999999990 to + 99.999999999 GHz in 1 Hz steps. The amplitude offset range is greater than f 100 dB in 0.1 dB steps. Least significant digits will be truncated for frequency and

amplitude offset entries.

Example

An 102.6 MHz up converter with 12.7 dB attenuation is placed between a signal source and the spectrum analyzer. The offsets can be set so that the CRT display shows the trace referenced to the signal as input to the converter.

Amplitude offset is entered as a positive value to com-

pensate (offset) the loss of the converter.

kHz,

MHz, or GHz for frequency and dB, - dB, mV and FV for

Note that the original REF LEVEL of 0 dBm is now changed to 12.7 dBm also.

92 Manual Operation

KEY FUNCTIONS

(,.,,, V -,

A, B, C, D

Frequency offset is entered as a negative value since the input frequency to the converter is lower than the output.

EFFECTIVE MIXER LEVEL

The effective mixer level is equal to the REFERENCE LEVEL minus the INPUT ATTENUATOR setting. It specifies the maximum signal level that will be applied to the input mixer for a signal that is equal to or below the REFERENCE LEVEL. A FULL SPAN key (0 - 2.5 GHz or 2 - 22 is 5 dB below the analyzer’s 1 dB compression point. The effective mixer level can be manually set from - 10

dBm * to - 70 dBm in 10 dB steps by pressing [ , (comma sign) and entering the desired

numeric keyboard. For instance, to set a mixer level at -40 dBm, press: (,,IIl , analyzer’s REFERENCE LEVEL is changed, the coupled input attenuator will automatically change to limit the maximum signal at the mixer to - 40 dBm for signals I REFERENCE LEVEL.

GHz)

sets the mixer level to - 10 dBm, which

eve1

through the

m d

(zl

. As the

AMPLITUDE UNITS

The following shift key codes immediately select the corresponding units for all the amplitude readouts: reference level, marker, display line, and threshold.

When a units change is made, all readouts are converted so as to preserve the absolute power levels of all the readouts. For example, a 0 dBm threshold level converts to 47.0 dBmV (50 ohm input) when dBmV units are called.

SHIFT KEY

FUNCTION

A. . . . . .

B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

[,,,,,

C . . . . . . . . . . . . . . . . . . . . . . . . . . . . dBpV

D . . . . . . . . . . . . . . . . . . . . . . . . . volts

(or FULLSPAN key) . . . . . . . dBm

The keys for these functions are located in the COUPLED FUNCTION group.

AMPLITUDE

UNITS

dBmV

‘In the Extended Reference Level Range (Shift I, under EXTEND REFERENCE LEVEL RANGE in this chapter), the effective mixer

level can be set to 0 dBm.

Manual Operation

H I, =,/

KEY FUNCTIONS

EXTEND REFERENCE LEVEL RANGE

Normally, the reference level can be set from - 89.9 dBm to + 30.0 dBm in coupled operation. The limits of the range can be extended to a maximum of - 139.9 dBm and + 60 dBm.

press B

The lower limit of reference level depends upon resolution bandwidth and scale.

Scale

Resolution Bandwidth

Minimum reference level

with extended reference level

10 dB attenuation

0 dB attenuation

lo9

linear linear

11 kHz 23 kHz sl kHz >3kHz

129.9 dBm

109.9 dBm

89.9 dBm

139.9 dBm

119.9 dBm

99.9 dBm

When the reference level is set at a minimum, the level may change if either scale or resolution bandwidth is changed. The extended range is disabled with instrument preset.

FACTORY PRESELECTOR SETTING

Activating provides a preset adjustment for each of the four frequency bands in the 2 - 22 GHz range. These preset adjust-

ments optimize the preselector tracking over the full 2 - 22 GHz frequency range. The tracking can be optimized at any single frequency with the the other three bands. (See Chapter 6 for more information.)

(,,t

= will reset the internal preselector to a factory set 2 - 22 GHz tracking range. The factory setting

()::::LJ

key. A @ adjustment in one band will not affect the preselector tracking in

MANUAL PRESELECTOR TRACKING

The internal preselector can be manually adjusted for a peak response in the 2-22 GHz band. m /

enables manual entry of a DAC number from 0 - 63 with the DATA knob, step keys, or numeric keyboard. The DAC reading corresponds to a voltage which sets a particular preselector tracking offset. The location of the MARKER determines the band (four independently adjustable bands) to be adjusted.

The Manual Preselector Tracking function is useful for peaking the preselector at locations where a stable CW signal is absent. For instance, drifting signals or pulse modulated signals do not easily lend themselves to the use of

. The automatic preselector peak routine depends on a stable CW signal. In this situation, a means for

manually tracking the preselector may provide a more reliable setting.

94 Manual Operation

KEY FUNCTIONS

u, K, N

MARKER SWEEPS

Stop Sweep at Marker, TALK after Marker

To stop the sweep at the marker,

press MARKER press

11*0

A marker must be activated to enter this sweep function.

Each time a sweep is triggered, it will stop at the marker, even if the marker has been moved. A marker being

moved when the sweep passes may not stop the sweep.

To disable the stop sweep at marker functions

press MARKER m or

In remote operation, the analyzer will not TALK until the trace sweep stops at the marker. TALK is suspended by keeping the HP-IB Data Valid line not true until the marker is placed.

I--]

and

I’a::]

MARKER TO NEXT PEAK/MARKER TO MINIMUM

Successive peaks can be identified by continuously using

can be used to find the largest signal. Then m K can be used successively to find the next largest signal.

Example

Press @ to find largest signal.

K to find next largest signal.

[

K. If a trace displays many different signal levels, a

! ! ! ! ! ! ! ! ! 1

Marker to Minimum

The minimum data value in a trace can be quickly located with B N.

Manual Operation 95

m, n, o, p, g, h, w

KEY FUNCTIONS

GRATICULE

AND ANNOTATION ON/OFF

The graticule and character readouts can be selectively blanked with key functions. This is valuable when alterna-

tive graphics are drawn on the CRT through the HP-IB.

Graticule Blank:

On:

press

[,,,,

press B n

Annotation

Blank:

On:

press press

(,.,,,

[,.,,,

0 p

CRT BEAM ON/OFF

The CRT beam power supply can be turned off to avoid unnecessary wear of the CRT if the analyzer is operated

unattended.

Beam off:

Beam on:

Reducing intensity

press

[,.,,, g

press

(,.,,,1

blanking

the traces does

not

reduce wear on the CRT

CRT beam power off does not affect HP-IB input/output of instrument function values or trace information.

DISPLAY CORRECTION DATA

The correction data generated from the error correction routine can be displayed.

Display correction data:

Do not display correction data:

The readout is detailed in this chapter under ERROR CORRECTION ROUTINE.

press m w press

[)b:;IJ

96 Manual Operation

.1 II* -5,

CORRECTION DATA DISPLAYED

.h” .*.. .*.,

.* .‘S n -..

KEY FUNCTIONS

(,.lrll

E, c, a, e, b, d

TITLE

The user can write a message in the top CRT display line. When the title is activated, the front panel blue

characters, number keyboard numbers, decimal, backspace, and space can be typed onto the top line starting at

the left of the display. The full width of the display can be used (total of 58 characters); however, marker readout

may interfere with the last 16 characters of the title.

(,,,,

Activate title:

Enter text:

To end a title:

E (shift light on) abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ

/4?L

= ()

,><

0123456789. [space] press

I--]

(shift light off)

A title will remain on the display until the title function is activated again,

la;l:]

is pressed, or an instrument state is recalled with @ . To erase a title without changing the instrument state, end the title function if still active, then press ( E

A + B + A enables the restoration of the original trace A after a a has been activated. A + B + A is executed with both Trace A and Trace B in

[,,,,

press m c.

When executed, m is turned off and the amplitude in trace B is added to the amplitude in trace A (in display units) and the result is written into trace A.

Additional A + B * A executions will each add another trace B response to the cumulative trace A

TRACE DETECTION MODES

One of four detection techniques can be selected for displaying trace information.

Mode

normal

sample

positive peak

negative peak

Access

FULL SPAN key

or [,,lrr a

(,.,,,jb

Use

l Most measurements

l Noise Level measurements

Zero frequency span waveforms for sweep times

msec

l Video averaging

Diagnostic aids for servicing

Manual Operation

(,,,,,

a, e, b, d

KEY

FUNCTIONS

Video

Signal

Track

Hold

AID CRT

COtlV~rtW

Memory

Display

During a sweep, only a specified amount of time is available for writing data into each of the 1001 trace memory

addresses. In two of these time periods, the positive and negative peak detectors obtain the maximum and

minimum video signal excursions, respectively, and store these values in

ahernate

trace memory addresses. This

technique allows a graphic presentation of noise on the CRT display.

Normal Mode

In normal mode, a detection algorithm selectively chooses between the positive and negative peak values to be displayed. The choice is made dependent upon the type of video signal present.

Data from the positive peak detector (signal maximums) will alway be displayed in the odd-addressed trace memories (1, 3, . . . 1001). If, within the time period following the storage of a value in an odd-addressed memory,

there is no change in video signal level, the positive peak detector value will also be stored in the even address. In other words, the even-addressed memory will also contain positive peak detection data if the signal during that time period is monotonic. Negative peak detector data (video signal minimum) will be stored in the even- addressed trace memory if the signal has a point of inflection during the time period.

’

Normal mode is selected with instrument preset.

Sample Mode

In the sample mode, the instantaneous signal value of the final analog-to-digital conversion for the time period is placed in memory. (As sweeptime increases, many analog-to-digital conversions occur in each time period, but only the final, single value can be stored.)

Sample mode is selected automatically for video averaging and noise level.

Positive and Negative Peak Modes

Positive and negative peak modes store signal maximums and minimums, respectively, in all trace memories.

98 Manual Operation

KEY FUNCTIONS

Readout

Here, the same signal response is displayed with each trace detection mode.

k!Yd

j, k, I

NORMAL

POSITIVE PEAK

SAMPLE

NEGATIVE PEAK

TRACE C

A third trace memory is available for the storage and display of trace information. Only the storage modes (view and blank) can be used.

View C:

BlankC: (,,,

(,,,1

These are analogous to the TRACE A and B modes discussed in Chapter 5.

Trace C cannot be written into directly from the analyzer except when video averaging is used.

Trace information from B can be transferred to C. To transfer from TRACE B to TRACE C, use

B-,C:

Manual Operation 99

(,,,,1

i, I, B, j,

KEY FUNCTIONS

The sweep will be suspended, the trace in memory B will be read and written into trace C from left to right in about 20 msec. Trace C is viewed. Sweeping will then resume from where suspended. The trace information in B is not changed.

To exchange traces B and C

The trace information in B and C is interchanged point for point from left to right in about 20 msec. If trace B is not displayed, it remains undisplayed. If trace C is not displayed, it remains undisplayed.

To store TRACE A into trace C. the trace A data must first be transferred into trace B:

press

or press m

(I*(rl

1 (which also erases last trace

(,.,,,1

i (which also saves last trace C in

Example

Comparisons of up to three different signal traces can be made simultaneously using traces A, B, and C. In this example, the modulation level of a signal will be changed for each trace. To start, clear the display with and

[,,,.,

(,,,,

The signal with the desired level of modulation will be stored in trace C:

Press

B and allow one sweep.

Press

(,,,,

1 which writes the trace from B into C.

Change the modulation level, allow one sweep and store in B with m B.

To view C, press m j.

100 Manual Operation

KEY FUNCTIONS

A, ‘2, H

Change the modulation level again and press m A, and store with

(,,,.

A. The three traces are differenti-

ated by intensity.

VIDEO AVERAGING

Video averaging is a trace display routine that averages trace responses from sweep to sweep without requiring a narrow video bandwidth. (Averaging with the video bandwidth is discussed in Chapter 8, COUPLED FUNCTION

m .)

Both video averaging and reducing video bandwidth are primarily used to improve the analyzer’s ability to

measure low-level signals by smoothing the noise response.

To activate video averaging (and sample detection mode),

press

(z] [??I

(DATA keyboard entry)

To disable video averaging, press

(,, @

CAUTION

Video averaging may result in an uncalibrated amplitude display when

frequency span

Resolution Bandwidth

Readout in the active function display area is “VID AVG

> 1000

100”.

The number represents the maximum number of samples (or sweeps) for complete averaging. The DATA entry can be used to change the maximum sample number in integers from 0 to 1000. A unity sample limit allows direct writing of analyzer response into Trace C (see Trace C below). A 100 sample limit is selected upon instrument preset. The higher the sample limit, the more smoothing possible. Averaging with high sample limits can provide more smoothing than the 1 Hz video bandwidth.

During video averaging, the current sample being taken is read out at the left of the display.

Manual Operation 101

I”;;!

KEY FUNCTIONS

The advantage of video averaging over narrowing the video filter is the ability of the user to see changes made to

the amplitude or frequency scaling of the display while smoothing the noise response. For example, when a 100

Hz video bandwidth is used with a 200

kHz

frequency span, the sweeptime is 2 sec. Almost a full sweeptime duration would have to pass before any center frequency change effect on the trace could be seen. If video averaging is used instead of the narrow video bandwidth, any change to center frequency will be seen immediately, even though full averaging will take roughly 6 sec. (Any change to control settings such as CENTER FREQUENCY FREQUENCY SPAN, etc., will cause the video averaging process to be restarted.)

Example

To display very low-level signal responses, very narrow resolution and video bandwidths are required. The accompanying increase in sweep time can make measurements cumbersome. Video averaging allows the display of level signals without the long sweep time.

RD=

“P

10 dW

-13.1

de*

.TTEN 18 dB

low-

Viewing a low-level signal with a video bandwidth of 1

Hz requires a 150-second sweep.

Disable the narrow video filter by pressing the

(wr(ll

key that is above the m key.

Start video averaging by pressing

(,.,,, h

Now the low-level signals begin to show quickly.

Changes to the frequency range or amplitude scale will restart the sampling to show the signals quickly, without having to wait 150 seconds. In fact, the video averaging shown took 42 x 300 msec = 12.6 sec.

Video Averaging Algorithm

The averaging of each amplitude point depends upon the number of samples already taken and last average amplitude.

n-l

Y”=y

’ Y(n-l) +TYn

102 Manual Operation

KEY FUNCTIONS

where

latest average amplitude value in display units

current sample number

tY.L

k, G, x, y, (, )

Tn _ 1

The new amplitude value,

last average amplitude in trace memory (TRACE A or

new amplitude entry from analyzer (Trace C)

is weighted more heavily by the last average

yn,

amplitudeij, _ 1

than the new

amplitude entry, yn.

When n equals the limit set (e.g. 100, the preset limit), the last average amplitude is gradually replaced with new data. Thus, the average will follow a slowly changing signal response, particularly if the sample limit is small.

Trace C

Video averaging requires the use of trace memory C. When video averaging is activated, the input signal response is written into trace C, the averaging algorithm is applied to these amplitudes and the results written into TRACE A. Thus, two traces are displayed: the input signal in C and the averaged signal in A.

Trace C may be blanked without affecting the operation of video averaging.

Press (,,rl) k

Trace C may be written into as traces A and B if a video average sample limit of one is selected.

If either trace A or B is in a write trace mode, the analyzer response will also be written into trace C.

EXTERNAL AND VIDEO TRIGGER

The front panel sweeptimes less than 20 msec. To eliminate the automatic refresh feature:

(.,l

and m trigger modes automatically keep the display refreshed in zero frequency spans for

For external triggering: Press

For video triggering: Press

B 1111

(,,,, b

LOCKING SAVE REGISTERS

After saving instrument states in one or more of the six registers, 1 through 6, the registers can be secured from being written over and destroyed. The recall function is not affected.

Lock: m

Unlocked: m

When locked, an attempt to

[,,,

will write “SAVE LOCK” on the CRT and no DATA entry can be made.

Manual Operation 103

Agilent 8566B Operating and Programming Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

CERTIFICATION

WARRANTY

ASSISTANCE

GENERAL INFORMATION

INITIAL POWER ON

Calibration

RF INPUT

Manual Calibration Procedure

CRT DISPLAY

Error Correction Routine

PLOTTER OUTPUT

FRONT PANEL OVERVIEW

Control Groups

REAR PANEL OUTPUTS

Recorder Outputs

Display Outputs

21.4 MHz IF Output

Sweep Plus Tune Output

10 MHz Output

Frequency Reference Input/Output

HP-IB Input Output Connector

IF and Video Connectors

External Sweep Trigger Input

FRONT PANEL CONCEPT

GENERAL DESCRIPTION

MAKING A MEASUREMENT

Example

DIRECT FREQUENCY AND AMPLITUDE READOUT

SAVE/RECALL

SHIFT KEYS

AUTOMATIC MEASUREMENTS

DATA CONTROLS

GENERAL DESCRIPTION

FRONT PANEL FUNCTIONS USING DATA CONTROLS

DATA ENTRY READOUT

PREVENTING DATA ENTRY

DATA KNOB

DATA STEP KEYS

DATA NUMBER/UNITS KEYBOARD

Negative DATA Entry

MULTIPLE DATA CHANGES

GENERAL DESCRIPTION

CENTER FREQUENCY

DATA Entry with CENTER FREQUENCY

Example

FREQUENCY SPAN

DATA Entry with FREQUENCY SPAN

Example

Example

START/STOP FREQUENCY

DATA Entry with START/STOP Frequency

Example

REFERENCE LEVEL

DATA Entry with REFERENCE LEVEL

Example

FUNCTION/DATA SUMMARY

GENERAL DESCRIPTION

ADJUSTMENT OF THE DISPLAY

CRT Display and Adjustments

DISPLAY SECTION LINE POWER

CRT DISPLAY OVERVIEW

Active Function

Traces

Locations of Permanent Readouts

Other Readouts

TRACE IDENTIFICATION

GENERAL DESCRIPTION

TRACE MODES

WRITE Modes (sweeping):

STORE Modes (not sweeping):

Trace Memory

WRITE Modes

STORE Modes

Example

TRACE EXCHANGE

TRACE C MODES